I still have and love my GameCube Nintendo.
RE4, Zelda:WW(except for that stupid, stupid Triforce shard deal), Fire Emblem, DK:JB, Metroid Prime, Prince of Persia, and Eternal Darkness have been some of the most enjoyable games I've played the last two gens.
That said, I've enjoyed the Xbox equally. Halo 1/2 has become one of my favourite series of games. Ninja Gaiden Black, well nothing needs to be said. Crimson Skies, KotoR 1, Red Dead Revolver, Panzer Dragoon Orta, JSRF(not as good as JSR), Psychonauts, and Phantom Dust all rule.
The PS2, I didn't like so much. No Warhawk, no Tomba, no Jumping Flash makes for a very sad gamer.

Here's hoping the PS3 picks up the slack. They've announced WarHawk, so that's a good start.
