I use GPodder in conjunction with the FM transmitter almost every day, its very good.
RSS viewer
Gonvert
Gweld - Highly addictive puzzle game
ECoach
GPXView - Great geocaching tool
OMWeather - Seems to be pretty accurate weather data.
Built in browser - Excellent
Media player. - Pretty good after installing extra codecs.*

*It could be my imagination but the sound quality seemed to improve after installing the extra codecs.