Really cool stuff:Augment - augmented reality, place 3d (or 2d) objects on designated markers
Google Sky Map - literally a sky map, and it works indoors!
ST Fake Caller - schedule fake calls (text may look too tiny on low-res phones, but still usable)
iRemote Suite - control your PC over wifi, also allows shell access *non-intrusive ads*
VR Mobile - Numbers. Lets you look at the accelerometer and microphone readings. Acceleration and noise level.
Flashlight LED Genius - Shake your phone from the lock screen to activate whitescreen/led light.
Disco Light - Self explanatory.
くまポン顔文字12000 - Kaomoji list, in Japanese.
Kaomoji Dictionary ((o(^o^)o)) - Kaomoji list, in English.
web browsers:Opera Mobile - web browser, remarkable for its text wrapping (fit paragraphs to your screen)
Boat Browser - web browser, can handle some sites that Opera can't, but has no text wrapping
Dolphin Browser HD
InBrowser - Incognito browsing. Self explanatory
Oh, and supports changing of user agents too.
Media players:Tunein radio - radio
Last.fm - radio
TTPod - music player
Moboplayer - plays quite a lot of formats
Games / emulators:The tiger emulators (may have been removed from the market)
Osu!droid - play Osu! (ouendan fangame) on android
Super GNES - for playing SNES games
FPSe ($$$) - Not free, I downloaded an apk of an older version. PS1 emulator, works like a charm, though sound emulation isn't perfect.
File management:Airdroid - access your android's files over any web browser
ES File Explorer - file manager; also allows to access your PC's files from your android over wifi (PC must have a user account with a password)
Connectivity:Speed Test
Chat/IRC:Messenger WithYou - MSN on Android
SimpleIRC - pretty decent IRC
Other utilities:Battery Notifier - notifies you if your battery is full from charging / low charge
StopWatch & Timer - makes sandwhiches and does your laundry (no not really)
nLiveCam - view your PC's webcam from your android
Media Converter- Converts media, like video to MP3, and stuff
Readers/Manga readers:Mangawhat
Manga Watcher - Not free
Perfect Viewer
fbreader - reading
kindle - reading
Chant - 4chan on adriond
Unsorted:My Guitar - guitar plucking
MusicGrid - easiest way to make music, just click around the grid and it plays notes
Todo.txt - task scheduler
Astrid - task scheduler
Zeam - launcher replacement
Launcherpro - launcher replacement
Sex Offender Tracker- Sex offender radar powered by BeenVerified
AppExtractor - Restore Data from Nandriod backup
OruxMaps - Truely free map viewer,need some time to learn.
Touhou Apps:*just search touhou, there's too many
Touhou Battery Widget - several characters and ways to report battery left (%, bar, numbers)
Touhou Bomb
erman - controls look wonky on low-res phones
Touhou Project Character Walk (1,2,3, X, and specific chars ) - have touhous crawl on your phone
THBGMPlay - plays Touhou BGM files from 6 to 12.3, can't seem to install to Android 2.3 tho