XBOX is better by far :o, it has a lot of games GameCube and PS2 dont have, like one of the best, Halo 2, the only thing ps2 had on XBOX is GTA: San Andreas, and its on XBOX also now.
Not to be a Sony fanboy but i think the PS2 is the better console. Not because of hardware, it has been proven PS2 is probably the weakest of the 3 current gen consoles, but the fact is that the games and the usage of Emotion Engine makes it probably the best choice out there.
I vote for the ps2, it has great games which I can/let download for free. I also voted for others. The pc, it has alot of other things you can do on it than gaming related stuff.