After E3, I was all up on the PS2's bandwagon, I was really impressed by how close the graphics were to the X-box version.
After playing the PS2 version on my couch this afternoon, I think I might be changing my tune. The PS2 version might still be the best, and definitely is if you want online play. But there is slowdown, something I've seen only rarely on either the X-box or GC versions of NCAA 2003 or 2004. Also, simming games takes FOREVER. Everything is slower on the PS2 -- simming, load times, saving to a memory card. For someone as impatient as myself, playing the PS2 version makes me think that I'm going to play dynasty games on the X-box this year.
If online doesn't matter to you, get the GC or X-box. Every system has the ability to download rosters, so that's a wash. PS2 and Gamecube have the best controllers, though the x-box controller is tolerable.
It should be good on every system this year, I just had forgotten how bad simming and saving files was on the PS2. Oh well, minor gripe. Just go out and get the game, it's even better than last year's masterpiece.
(BTW, simming is a function of CPU speed -- the PS2 has the slowest CPU amongst the modern consoles.)