Killer apps for me.
1 VLC player
2 Skype (seems to be a no go unfortunately)
3 Oolite would be great excellent remake of Elite one of the best games ever.
4 Opera and FireFox
5 Scummvm.
6 CBM 64 emulator
7 Amiga emulator
8 Mame
9 Mess
10 Mupen 64
Most desirable thing is that you can...