I guess its email mainly. Lately Facebook, but that's unusual for me. Also BeWeather, Pod Trapper, and the media player. My Berry doubles as a PMP.
Oh, and Tapatalk.
Ascendo Money
Any GPS app
Tether
QuickLaunch/ShortCutMe
MeterBerry
BerryBuzz
BBSmart Alarms
Brio Camera Light
PatternLock (I use mainly for locking call screen)
PDF To Go (I use this way more than the other Docs To Go tools)
Seems like a lot but they're all pretty important to me.