Xbox if you like graphics and online play, if your friend has xbox you guys can link your systems together and have deathmatch type games with seperate tv's, no split screen cheating.

PS2 if you like their third party support and their exclusive title's.

Gamecube if you like kiddie party type games and substandard graphics.

I have all 3 systems and will be getting xbox 360 when I can find a premium system for sale at MSRP.