If I would rate the systems right now it would be:

1. X-box
2. PS2
3. Gamecube

PS2 is more popular right now but I think overall X-box is the better gaming experience. I think PS2 and X-box wouldn't even be in the same ballpark if it wasn't for Grand Theft Auto III. The X-box is a better system cable of producing better games.

As for Gamecube, it has potential and the Square announcement gives it a good chance of a comeback... but I really am amazed at anyone that can say it is the best right now. There are about five future Gamecube titles I am excited about, six if you include the Square announcement that I will take a wait and see approach to (remember Square was also exclusively going to make games for the N64, and I wouldn't be surprised if Sony makes an offer they can't refuse), but Gamecube's current games are weak to say the least. Smash Bros rules, as does Star Wars, but I think the time is past to quote those titles, and Nintendo hasn't released anything else to make me say "I'm glad I own my Gamecube", so until Resident Evil comes out, my Gamecube will collect dust and my X-box will receive my console gaming time.