Well, since the Xbox came out, I've hardly played on my PC at all. Now that Xbox Live is out, I'm almost in my perfect gamer heaven (when a few more Live titles come out I'll be there).
I had played on my GameCube a bit... but Metroid was a huge letdown for me... I think I'm the only one that feels this way, maybe because I don't hold Nintendo in any high regard as I'm totally platform agnostic, heck I even owned a 3DO. But since Xbox Live hit, PC, GameCube are gathering the dust and I just outright sold my PS2 as I'm totally happy with the Xbox library of games, and the PC can pick up the scraps. I think I'll sell my GameCube as well, as their is absolutely nothing on the horizon that excites me for it.
To each his own... but I give mad props out to the Xbox, it's games and especially Xbox Live... it has made me one VERY happy gamer!