Well, being a Nintendo gamer, I'm obviously at least a little biased, but I also have a good PC, and I notice that more than half of the good games on the PS2 and Xbox end up on the PC anyway...so how can the GameCube be "obsolete" if there are still about two more years of actually-exclusive games yet to play? Granted, for the next couple years I'm just assuming there will be some great games, since I'm thinking some surprise hits we haven't even heard of are being cooked up, and you know, The Legend Of Zelda is always worth the wait. But this Christmas alone there are enough releases to keep me revisiting the local Blockbuster for the next few months (I only rent about twice a month)...games like Baten Kaitos, Metroid Prime 2: Echoes, Mario Power Tennis, Mega Man X: Command Mission, GoldenEye: Rogue Agent, LotR: The Third Age, my brother wants to rent Amazing Island, there are even some older GameCube games I have left to play, even.
I think the number of titles on the PS2 and Xbox don't mean as much as people think they do. At least for myself, a self-proclaimed "hardcore gamer", who will play most any genre and not care too much about if it's rated E or M, though there's a bias there. I just think that if people didn't count the generic games, the games they would never touch, and the games that they didn't have time for, that would leave them with the same amount of game play time as GameCube owners. My friends, PS2 and Xbox owners, keep bragging about the number of games they could have, but they play a lot less than I do, and I'm more than busy enough with my 'Cube. And if the 'Cube can keep me and a lot of people busy, it can't be obsolete. Certainly not at this point, while we're still in this generation of consoles, even if it is mostly downhill from here.
Plus, "obsolete" implies a technical view, like you could say the NES and Super NES were obsolete even if you still found them fun. But the GameCube is in a few ways technically superior to the PS2, so if the PS2 isn't obsolete, how could the GameCube be?