I have a PS2, the first one that came out, i'd prefer to have the silver one thouh, or the super-slim version.
GameCube is rubbish, when you compare all three the gamecube comes out the worst every time, and the best is the XBox, because of it's graphics and all round performance. You can also get a lot of good games for the XBox, but they all seem to be more expensive than the games for the GameCube or PS2.
For example, FIFA 2005, a fairly new game, is ?45 for the XBox but can be bought for only ?32 for the PS2.