[T-Mobile Samsung Galaxy S II SGH-T989] Sui Generis:
I have put together a list of good applications. There are (30) to begin with and almost all of them are free. I cannot say that they are "must-have" but they are "the best". Please feel free to add yours but only after you tried it, you checked your phone resources while have it installed (e.g. memory usage, battery drain, etc) and, of course, if your level of satisfaction was high. PLEASE REMEMBER THAT THIS IS NOT A THREAD TO PROMOTE FIRST,SECOND OR THIRD-PARTY APPLICATIONS. PLEASE!

LIST OF BEST ANDROID APPS FOR SAMSUNG GALAXY SII T989

1. Advanced Task Killer Free 1.7.9

2. Astrid Task/To Do List

No other app gives as much detail to to do lists as Astrid. Its "advanced" options lets you set priority levels, integrate with Google Calendar, sync with Google tasks, and set up tags, alerts and periodic reminders. Astrid keeps it easy, for the most part, but also offers deeper settings if you're the obsessive, customize-everything exactly-how-you-want-it type.

3. Astro File Manager 2.4.2

Metago, www.metago.net/astro

We love apps. You love apps. Thing is, they can take up valuable space on your phone. To avoid running out of space, download Astro. The app lets you back up apps on your SD card; you can't run them from there, but you can swap out apps you aren't using.

4. Bonsai Blast 1.5

Glu Mobile, www.glu.com

Great games for Android aren't as rare as they used to be, but that didn't keep us from including Bonsai Blast once again.

5. doubleTwist Player 1.0.1

doubleTwist, http://twist.to/android

doubleTwist Player for Android is a slick media player app that helps make up for the lack of iTunes on your phone. Combine it with the desktop version of doubleTwist, and you'll turn your Android device into a portable multimedia powerhouse that syncs music, (un-DRMed) iTunes playlists, and videos as well as any Apple hardware does. It's a must-have for all music lovers.

6. Facebook for Android 1.2

Facebook, www.facebook.com/apps

This is the "official" Facebook app on Android, and it serves its purpose well enough. You can post status updates, take/upload photos, and check your news stream. It's a lot faster than using the Facebook Web app, so it's the best option on Android to stay connected to all your Facebook friends.

7. Google Voice 0.3.4

Google,www.google.com/voice

Google Voice for Android remains the best way to use Google Voice on a mobile phone. If you have a virtual Google Voice number, you'll be able to make outgoing calls and SMS messages easily, including international calls that run about 2 cents per minute. This app also lets you integrate your phone's built-in address book and call log for voice calls. There are other third-party apps out there that tap into Google Voice, but stick with Google's native app; it works almost seamlessly.

8. Photoshop.com Mobile 1.2.0

Adobe, mobile.photoshop.com

Still the best free photo editing app out there, Adobe's Photoshop.com Mobile gives you an arsenal of tools to use on your Android phone. You can crop, rotate, color-correct, or change images to black-and-white with a beautifully intuitive interface. The app integrates with free Photoshop.com online accounts, but unfortunately, not other popular services such as Flickr.

9. Replica Island 1.3

Team Replica, http://replicaisland.net

Replica Island is perhaps the most sophisticated free game app on the Android platform. As a platformer, where you collect coins and avoid enemies, it's similar to older video games like Mega Man and Super Mario Brothers. But it's a must-have game that provides 40 levels of fun, and it uses phone features, such as the accelerometer quite well.

10. Ringdroid 2.3

Ringdroid, code.google.com/p/ringdroid

Ringdroid is more than a ringtone app; it's really an audio editor for your Android phone. You can use it to clip audio files to make ringtones, but also for any other purpose—for example, sending audio recordings to friends. Just take almost any unprotected audio file that your Android phone can play, slide two sliders to the beginning and end of your clip, and in an instant your new sound is done.

11. Talk To Me Classic 1.7.8

Flaviu Negrean, www.flaviuapps.com

This nifty app has been updated since it first made our list in 2009. Originally, Talk To Me translated only English, French, Spanish, German, and Italian, with its speech-to-speech functionality. Now it has many other languages from which to choose. On top of adding languages like Chinese to its speech-to-speech arsenal, you can now translate many other languages by typing what you want translated into the program. This app is a must-have aid for any traveler.

12. The Weather Channel 2.3.22

The Weather Channel, www.weather.com

If you're in the market for a free comprehensive weather app, The Weather Channel app is as good as any. It gives you everything you'll need to know before you head out for the day—hourly, 36-hour, and 10-day forecasts, multiple locations, and live video from the TV channel. The app automatically updates your location using GPS, and its home screen widgets will keep you informed if it's time to get your umbrella out.

13. Wheres My Droid

Free

If you're anything like me, you've "lost" your phone many times only to find it tucked away in a jacket pocket or some other obvious—or not so obvious—locations. Now you can save yourself plenty of worry with Wheres My Droid [sic], which forces your phone to ring at maximum volume or vibrate when the phone receives a text message containing a specified phrase, such as "Where's my Droid?" The app can also tell you the phone's location, as long as its GPS is enabled.

14. ooVoo Video Calls

Stable and reliable video chat apps for Android aren't easy to come by, but ooVoo is terrific. The Android video chat app supports group video, voice calls, and instant messaging—across iOS, OSX, Android, and Windows. Not only do you get solid Android video calling, but you can practically video chat with anyone.

15. Google Translate

The latest Google Translate update takes the app to the next level: Speak the words you want translated, and you'll get the result instantly, either spoken or on screen. It can be useful when you are abroad, if you have data roaming enabled.

16. Google Body

For Android 3.0 Honeycomb tablets

Explore the intricate complexity of the human body with beautiful, interactive 3D models. The app offers different anatomical layers, and you can search by bones, muscles, or other parts.

17. Jefit

Professional Weight Training/Bodybuilding App designed by serious bodybuilders.

The JEFIT Android Bodybuilding App designed by serious bodybuilders to improve an individuals workout in the gym, ease of tracking body statistics, create custom routines, detailed exercise database, and two-way synchronization with online server to store information and keep logs of progress.

JEFIT Free Android Workout Application is essential for bodybuilding and fitness enthusiasts alike and the best way to keep track of your workout data without the use of a paper and pad.

18. Barcode Scanner

Scan barcodes on products then look up prices and reviews. You can also scan Data Matrix and QR Codes containing URLs, contact info, etc.

Also share your contacts, apps, and bookmarks via QR Code. This is why contacts permissions are needed.

19. ★ Evernote

Evernote turns your Android device into an extension of your brain.

Evernote is an easy-to-use, free app that helps you remember everything across all of the devices you use. Stay organized, save your ideas and improve productivity. Evernote lets you take notes, capture photos, create to-do lists, record voice reminders--and makes these notes completely searchable, whether you are at home, at work, or on the go.

20. ★ Tasker

Automate everything from settings to photos, SMS to speech. ADC2 prize winner.

Total Automation, from settings to SMS. ADC2 finalist!

* Triggers: App, Time, Day, Location, Hard/Soft State, Event, Shortcut, Widget, Timer

* Actions: 175+ built-in, any Locale-compatible setting plugin

* Tasks: loops, variables, conditions

21. Beautiful Widgets

Beautiful set of widgets including clock+weather, with some toggles

Beautiful set of Widgets containing clock widget, clock and weather widget, weather widgets, date widgets and toggle widgets with skins/themes support! Now with more widgets and layouts!

Selected by Google as an Android Editor's choice and first paid application to reach 1 million of downloads!

See why it is the best Android clock and weather widgets and the only choice for thousands of users!

22. Embiggen

Use words to their fullest potential: Embiggen them!

At a bar, at the library, in class, even in the comfort of your own home. Just type in a word or phrase and watch as small words become big words on your phone's screen. No word is too small to embiggen!

101 ways to use Embiggen:

- Tell that girl across the room she's cute, or ask the guy at the library for his phone number!

- Pick a fight with someone on the bus without saying a word!

- Command your literate dog to fetch your slippers!

- and 98 others!!!

23. Chess Free

The timeless game of intellectual warfare. Are you a grand master in the making?

Chess Free is the best free Chess game on Android!

It is currently the highest rated free chess on Android (at time of writing), from the 30+ free chess programs listed.

24. Easy Uninstaller

Simplist & fastest uninstall tool for android.

Easy & fastest uninstall tool for android.

#Feature

*Batch uninstall

*Fast uninstall by one click

*Show app name,version,update time,size

*Search app by name

25. Google Goggles

Search the real world by taking a picture.

Search by taking a picture. Goggles uses image recognition technology to recognize objects and return relevant search results. Identifies products, famous landmarks, storefronts, artwork, and popular images found online. Goggles can translate words in English, French, Italian, German, Spanish, Portuguese & Russian.

26. Handy Calc

handyCalc is a powerful calculator with automatic suggestion and solving which makes it easier to learn and use.

With almost all the features you can imagine on a calculator, waiting for you to explore.

27. VLC

It's only in super pre-alpha type stage but VLC for Android is VLC, our favoritest video player in the world. Play all the movies, tv shows and videos you've accumulated in your Internet career on your Android phone.

28. Backgrounds

Ain't nothing like pretending your old phone is brand new than switching up the wallpaper. Backgrounds has a ridiculous, ridiculous amount of options to choose from (over 10k!).

29. AK Notepad

There's plenty of note apps that throw in snazzier features but the beauty of AK Notepad is in its simplicity: it's a basic yellow pad that let's you jot down what you need.

30. Google Earth

It's, like, the entire world...on your Android phone. Google Earth is cooler than ever when you're using your fingers to manipulate it, seamlessly zooming around the globe and diving into various places to take a closer look.