Google Music
System Tuner
Simple Notepad
Droidforums
Xda Developers
Rootzwiki
DROID light
AnyCut
Google Currents
Google +
Android Pro Widgets
Getjar
PlayerPro
Voodoo OTA RootKeeper
Shadow gun
DukeNukem 3d
NFL Mobile
If you want some limited customization (change font or boot animation) and TB-like features, Motomizer is a good free app (I ended up donating even though the free version had full features).
Also, get Amazon App Store. They offer a free app every day. Most are $.99 apps but once in a while they will have a really good app. They offered Cardio Trainer, Documents to Go and Executive Assistant to name a few.