Here’s my round-up of the top free Android apps organized under relevant categories. Simply click on an app name to go to its download page:
Music & Audio

Probably the best free music player for Android. Play, manage and sync music from your desktop to your Android device. If you have Winamp 5.6, then it also supports wireless desktop sync, iTunes library import and access to SHOUT cast radio stations.

A nice all-in-one music, radio and video app. Sync and Play your iTunes playlists, podcasts and videos – it even imports ratings and playcount from your PC or MAC.

A simple music player that also facilitates sharing on Facebook & Twitter with automatic addition of the song’s YouTube link in the post.

PLAY by AOL is a beautiful, free, fun and simple app to listen, share (Twitter and Facebook) and discover music! Like Winamp, it also let's you stream SHOUTcast radio.

Another good looking music player with easy browsing and playback features apart from Flickr photo-stream of artist images, Podcast support, Facebook 'Like' integration, Bluetooth car audio support, Audioscrobbler support and Lock screen widget.

Enhance the audio FX in the stock music player on your Android device with this app to provide a rich 3D experience on headphones (stereo widening and reverb), bass boost and equalizer. Includes preset (Classical, Dance, Rock, Pop, etc.) and customizable 5-band equalization.

A music app with some cool eye-candy. Just select your navigation preference (artist or album) to get a 3D view of the album art. Select an album to get information & links to buy it from Amazon, 7digital etc. and links to Last.fm, YouTube etc.

You don’t need a Google Music account to use this app. It can be used as a local music player too. Nice eye-candy and other standard music player features make this a nice-to-have music player app for your Android.

If you’re an Amazon cloud music service user, this is a must-have Android app. Can be used to play the music on your device or the music stored in your cloud drive. Also facilitates shopping and saving to the Cloud drive.

This app displays synchronized lyrics while listening to a song in more than 40 languages. The audio player boasts of quick YouTube search and access to Shoutcast Internet radio. Also allows user to find and follow friends/TuneWiki users, explore Song Maps, real-time Top Charts and etc.

Apart from simply playing music, this app analyzes your tracks and creates a tag cloud. If you select a tag, it builds a playlist automatically – however this feature works best when you have at least 20 albums. The app also downloads album covers and scrobbles
last.fm.

The music player on the famous MIUI ROM is now available as a separate app for all Android devices and dig this – and it doesn’t require rooting! Apart from nice eye-candy, it comes an equalizer, local or online lyrics sync (live), sleep mode, play & download, ID3 editing, album art etc.

A useful music tag editor featuring Standard ID3 tag support, music title, artist and album editor, quick search and preview, easy album cover finder with "lucky cover”, supports mp3, ogg, m4a and flac.

Download missing cover art for your music tracks or albums from LastFM and MusicBrainz; also supports manual cover load from gallery.

Hold your phone towards the music you are listening to and Shazam will help identify the track, buy it, check out related videos, get lyrics, share it with friends, read reviews and more.

An alternative to Shazam with unlimited free usage - sometimes identifies songs just by humming or singing to it! Features geotagging options, Facebook and Twitter sharing, previews, purchase links, full length YouTube videos, and your favorite artists' top songs & bios and more.

Have you ever listened to music in your car at full volume, and then when you plug in your earphones, forget to lower it? This app helps you to control such instances providing a simple two-slider configuration to preset volume levels when the headphone or plugged-in.
Musician

This app allows you to alter the playback speed of your audio files "on the fly", without changing their audible characteristics. Useful to slow down audio for transcribing, work out a guitar/piano solo or speed it up to save time listening to audiobooks/podcasts etc. Works with MP3 and WAV.

Need to know the correct tempo of a song? This simple app will calculate the beats per minute (BPM) – useful to communicate tempo information of songs on your set-list to your worship team.

A free, stable and simple metronome with no ads.

Rhythm Master is a simple and intuitive metronome application supporting tempo up to 500 bpm.

This is an advanced guitar chord and scale finder for guitarists. Displays and plays chords in different finger positions. Also supports left-handed guitar players.

Another app to find chords for Guitar, Ukulele, Bouzouki/Mandolin, Banjo and Cavaquinho. Other features are 5700+ chord positions, playback/autoplay, chord information (root, 3rd, 5th, 7th...), left-handled support and more.

This is an interactive guitar app from Gibson that features a standard chromatic tuner, metronome, chord chart, guitar lessons from Gibson and more.

For pianists/keyboardists, this app displays the formula of a chord, notes according to a selected root, positions of notes on the piano keyboard and also plays the selected chord/scale.

Search, find and save chords for songs with this fantastic app – probably the only free app available for this purpose. Great for taking chords/tabs for songs wherever you go. Saved song chords can be viewed offline too.
Social

The official app for Google+ lets you share with and get updates from your circles or see what people are saying about things nearby. Supports instant uploads of media from your phone to your own private album in the cloud automatically for later sharing if your wish. Also supports Huddles.

Facebook for Android makes it easy to stay connected while on the go. Share status updates from your home screen, chat with your friends, check out your News Feed, review your upcoming Events, look at your friends’ walls and user info, check into Places, upload Photos etc.

The official Twitter app enables you to browse interests, find & follow friends, tweet, retweet, favorite, direct message privately with your followers, share photos, videos and web pages, real-time search, view maps, trends etc.

For more features to manage Twitter, check out this highly rated app for simultaneous posting to Twitter and Facebook, retweet with or without comments, use Twitlonger, conversation thread view, Twitter lists, customized Twitter notifications, enhanced search etc.

Foursquare helps you explore the world around you. Keep up with friends, get insider tips, and unlock discounts and rewards. You can easily tell friends where you are, share pictures and get their comments.

If you want a single app to manage Twitter, Facebook and Foursquare, this one will do the job. TweetDeck makes it easy to stay up to date and organized no matter where you are. Track replies, comments, likes and retweets in your 'Me' column, speed dial your favorite contacts etc.

An alternative to TweetDeck for Facebook and Twitter. Get updates and share photos, videos and location using the service of your choice like Plixi, yFrog, TwitPic and YouTube. Supports multiple Twitter accounts, cross-posting, lists, retweets, Twitlonger & Salesforce Chatter integration etc.

LinkedIn for Android lets you access your professional network while on the move. Get the latest updates and messages from your network and keep them up-to-date with your status in real-time.

Slowly scroll notifications like missed calls, new SMS messages, calendar appointments, voicemails and the latest posts from your Twitter and Facebook streams right on your home screen as a live wallpaper. Works in portrait & landscape mode.
Songwriting

This is a simple app to have to search for rhyming ideas. Simple input any word and tap 'submit' to get words that rhyme with it.

To find imperfect rhymes for words, there's no better app than B-Rhymes - it gives you words that sound good together even though they don't technically rhyme apart from regular rhymes.

Ever thought “wish I had a better word to replace this!” in the middle of writing a song? Here’s where this app can help. This app is a free dictionary and Thesaurus with access to over 1.4 million words. A word search generates synonyms, antonyms, similar and related words in addition to hypernyms (more generic words), hyponyms (subordinate words) and meronyms (part names).
Sometimes it also gives illustrations on how a word is used. All of these should help trigger lyric ideas or improve lines in the song by using substitute words suggested by this app.

This is an all-in-one app to jot down song ideas, use the voice note feature to record melody ideas, share files with co-writers and sync your writings with your other computing devices using Evernote’s syncing abilities. This is a must-have for songwriters!

A simple app that allows recording of uncompressed audio at a user determined sample rate. The only issue is it saves the recordings to the root of the SD card with no option to change the location – leads to housekeeping later on. Apart from this nag, it’s a great app for recording.

Another nice recording app that supports high-fidelity uncompressed recording, organizing recordings into projects, emailing recordings, adding text labels and more. Also allows opening files with
Ringdroid.
Worship Planning

If you already have an account with Planning Center online, then this app is a must-have. It has most of the features available on the website and is probably the only Android app of its kind available for worship ministries at the moment.
Video

The official YouTube app is as good an option as any for all YT fans. Supports all standard features including in-page playback, simple UI, personalized home-screen video feed, fullscreen playback and more.

If you want to download YouTube videos, then this is the app for you. It locks into multiple connections for faster downloading, supports multiple downloads, flexible resolution options, conversion to MP3, playlists etc.

The USP of this app is it plays just about any video file format including subtitle track formats like sub, .ass, .mpl., .srt. etc. Other features include high quality full-screen video playback, playlist management, rich UI, subtitle options and more. One irritant is it plays ads whenever a video is paused – overlook this and you have the perfect video player for Android.

Another solid video player app for Android! Plays a wide variety of video and subtitle file formats. Features excellent playlist management features and queuing of multiple videos for continuous playback. Also displays thumbnails of videos, media library etc.
Office & Productivity

The official Android app for Google Docs facilitates users to create, edit, upload and share documents. At present it’s great for viewing, but has some way to go before it can be used for comfortable editing though.

Jorte is a personal organizer app that has the look and feel of a physical paper organizer. It features a customizable calendar and scheduler, widget support, data import via CSV files and even syncs with Google calendar & Gmail.

An easy-to-use note-taking app that automatically enriches your notes with links, info and relevant offers. Also doubles up as a task/to-do list manager with reminders. Also supports barcode scanning, photo/voice memo, home-screen widget, alerts etc.

The official PDF viewer for Android devices from Adobe featuring high quality & quick PDF viewing including PDF Portfolios and password-protected PDF files, text reflow mode to adjust document content to fit screen size, choice of viewing modes (Single Page or Continuous Scroll) etc.

The official Android app to read Kindle books on your Android device with access to thousands of free books. The interface is beautiful and user-friendly. Comes with Amazon Whispersync to automatically sync your last page read, bookmarks, notes, and highlights across devices (including Kindle), so you can pick up where you left off on another device. You can customize background color, font size, portrait/landscape reading mode according to your preferences. Also supports dictionary word lookup with 250,000 entries, definitions, Google and Wikipedia links.

A useful e-book reader to download and read thousands of ebooks including a large collection of best-sellers, new releases and classics (many of them for FREE) or import your own ePub and PDF files.

Another feature-rich e-book reader from the famous GO team. The app provides a pleasant reading experience with features like multiple format support, file import, full text search, reading mode etc.

This Android app turns the camera into a Scanner to digitize any paper document by taking a photo. CamScanner can auto-crop images, enhance image quality to create an industry standard PDF file, facilitate batch scanning of multiple pages, upload files to Dropbox, Google Doc and Box.net.

A simple and highly rated app to scan/read
QR codes, create QR codes from Contacts stored in your phone and more.

This is a cross-platform sharing app to transfer photos, apps, messages and contacts from one phone to another. Works between Android and iPhone too!

Probably the best looking feed reader for Android featuring an award-winning, eye-candy rich interface to follow your favorite news sites/blogs and share content via Twitter, Facebook and Email. Also facilitates bookmarking (Instapaper, Read It Later), connecting with Google reader etc.

Another good looking news reader app with features similar to FLUD. Supports syncing with Instapaper, Read it Later and Evernote, sharing via Facebook, Twitter and email, offline syncing, Google reader integration etc.

A useful app that tracks and updates your usage information (calls, texts and data) and warns you when your usage is near your plan limit.

An amazing file/app manager, task killer, dropbox & FTP client, file compress/uncompress utility with a plethora of features to help you stay productive.

Another powerful file/app manager with features similar to ES File Explorer.
Bible

A user-friendly Android app for Bible reading, featuring 50+ free translations, dozens of reading plans to help you read the Bible and track your progress, offline Bibles, Twitter and Facebook connectivity and bookmarking favourite verses. With a YouVersion account, you can also sync notes.

Another excellent app that lets you read, listen to, and share the Bible in 500+ languages including dramatized audio. Allows sharing any Bible verse via Facebook, Twitter, SMS, Email or Copy with just a tap. Comes with daily Bible programs and ability to bookmark, highlight, & add notes. With a free Bible.is account, you can also sync bookmarks, highlights & notes between Bible.is Online and your Android phone.
Email

The official Gmail app come with push, sync, conversations, integration, search etc. Standard Gmail features like stars, labels, multiple accounts and more are also supported.

Yahoo! Mail users have their own Android app too. The app for Android supports multiple Yahoo! Mail accounts, photos preview, enhanced Yahoo! Messenger integration, push notifications, mail attachments, rich text composer with emoticons, smart folders and search.

Let’s not forget Hotmail users – The official Microsoft mobile app for Hotmail includes features like push email, synced calendar and contacts, folder/sub-folder view, multiple accounts and more.

A free and powerful open-source email client for Android - with search, IMAP push email, multi-folder sync, flagging, filing, signatures, bcc-self, PGP, mail on SD & more.
Instant Messaging

If you’re looking for a multi-protocol IM app for Android, it’s hard to look beyond IMO. Comes with an intuitive design and supports almost all popular IM protocols like Skype, Facebook, Google Talk, MSN, MySpace, AIM/ICQ, Jabber and Yahoo. Apart from text, it also features voice IM, sending photos & video through its own file sharing service, chat recording etc.

Probably the closest alternative to IMO; apart from basic chat, this app also facilitates sending pictures and syncing with Trillian for Mac, Windows and Web. You can also use Trillian-to-Trillian messaging and save on SMS costs! Requires creation of an account with Trillian though.

One of the most popular multi-protocol IM app with support for MSN, AIM, ICQ, Facebook, Yahoo, GTalk, MySpace and Hyves.

The official Yahoo! app is a nice option if all your chatting is only on Yahoo!, Facebook and Windows Live. Features free voice and video calls, free international SMS to select countries, photo & video sharing etc.
Browser

This browser for Android matches the sleek looks of the iOS browser and features screenshots, advanced bookmarks manager, smart address/search bar, built-in download manager, Adobe Flash player support, app-to-SD, link sharing, multi-tabs, day/night mode and more.

Considered by many as the best Android browser around. Supports tabbed browsing, lots of add-ons, magazine layout mode, smart address bar, bookmarks importing, gestures, themes, 16 languages etc.

One of the fastest browsers for Android devices, it has a unique feature of compressing web pages before rendering to decrease page load times and save money too as the compression reduces data usage to almost 1/10
th of the data when using normal browsers. Other standard features like pinch zoom, bookmark synchronization, speed dialing, built-in Twitter & facebook support, games and free apps etc. The drawbacks are it doesn’t play video and sometimes the interface looks a bit too busy.

For a fast web experience, Maxthon is probably the most effective browser for Android devices. Ad-free with support for syncing, themes, add-ons, tabbed browsing and more!

Another popular browser that’s also fast and packs a ton of features. One unique feature is its ability to transcode Flash content into HTML5 thereby enabling flash video file playback. Other features include, Facebook quick view, built-in feed reader, search across multiple sites, private browsing etc.
Cloud Computing

The official Android app for the popular cloud storage service lets you save files to your Dropbox, share files with contacts, save email attachments and edit documents.

Considered the best cloud storage and syncing service by many, its Android app instantly backs-up photos taken on mobile camera, access files including download, music streaming, file sharing etc.

This is the official app for another well-known cloud storage service – Box.Net. Facilitates Sharing/viewing/downloading/uploading/deleting of files/folders at your Box.Net account.

Known as the more secure option among other services like DropBox or Sugarsync, this is its Android app. Allows you to view files, create/share file links, mark favorites and download files.

This app uses the Google Cloud Print service to print files in your Android device. Currently supports printing of pdf, jpg, jpeg, docx, ods, xls, xlsx, ppt, odp, txt, doc and xps file formats. Other features are SMS/Email printing, webpage printing, clipboard printing etc.
Keyboards

This is a multi-purpose keyboard supporting a wide variety of languages (Afrikaans to Hindi), voice input, themes, multi-touch, gestures and more.

Another smart alternative keyboard for Android with support for multiple languages, gestures, text prediction, dictionaries, contacts/SMS import etc.
Camera & Image

A nice alternative camera app for Android that facilitates snapping photos with various effects.

This is a cool photo app that applies an ageing effect on photos to give them a pleasing vintage look.

Another one trick pony like the Old Photo app that applies a sketch effect on photos and images.

A popular app to apply effects on photos and images; comes with hundreds of effects to create photomontages, contact icons, animated effects, virtual postcards, phone wallpapers and more!

Adobe’s photo editing app for Android supports editing & sharing photos; also allows crop, color adjustment and artistic effects.

One of the best camera apps around with zoom to take quick photos and apply cool filters and effects like black & white, lomo, thermal on them. Also comes with photo sharing options (twitter, facebook, email etc.)

The official Android app from the popular Photobucket service to edit photos applying fun effects on them and share them on your favorite social network apart from Photobucket.

Another fun camera app to take photos, apply cool effects on them and share them on various social sites.

A one-stop app to browse, batch upload/download pictures stored in various accounts like Picasa, Flickr, Smugmug, Facebook, Photobucket, Windows Live, Tumblr, Deviant Art, Imgur and your SDCARD. Also supports slideshows, batch edit, set-as wallpaper, geolocation, album update notifications etc.
Blogging

The official Blogger app to publish posts with pictures, labels and location information. Supports post-list viewing and switching between multiple accounts.

The app of choice for wordpress users (wordpress.com and self-hosted wordpress blogs), it comes with standard features like writing new posts, editing content, managing comments view stats etc.

The official app for Tumblr bloggers to post photos, video, quotes, chats, links and text. Supports home-screen widget, multiple blogs, viewing and replying to messages, saving drafts, queuing posts, customizing tweets etc.

An easy-to-use blogging client app for Android with support for multiple blogs/accounts, feeds, rich text editing, uploading photos, YouTube videos, read/post comments, geo-tagging, sending links to Twitter/email etc.
Security

Anti-Virus Free is a free app from AVG to scan apps, settings and files in real time, find/locate lost or stolen phone via Google maps, backup/restore apps/data, lock and wipe phone, kill slow tasks and browse the Internet securely. Also supports multiple languages.

This is a cloud-based security app to protect against malware that also features a missing device tracker, task manager, app manager, live updates, a strongbox to hide sensitive data etc.

A useful cross-platform app (works on Android, Windows, Mac OS X and Linux) to store all your passwords and sensitive information in an encrypted database accessible through a master password.

Another app to store passwords and other info securely using a master password. It also backs up data to DropBox over HTTPS in an encrypted format. This is a free and ad-supported version.
Disclaimer: The above list was compiled voluntarily and reflects the author’s opinion. VotivePraise and/or its author are not responsible for any damage/data loss/any other problem that may arise from the use of any of these applications.
What are your favorite Android apps?