On Amiga:
Directory Opus 4.xx
AmigaAmp or Amplifier (one is a little better, but can't remember)
PersonalPaint
Non-Amiga:
VLC (works well on all platforms)
Firefox (same)
Celestia
PalmOS: grin
RFBackup
YAUC (Yet Another Unit Converter)
Planetarium
MathU
Noah Pro
ISilo