For me, I've never even thought to compare the two platforms. I'm practically incapable of it. It's always been PC + Nintendo system + possibly another console if it's performing better than the latest Nintendo console (PS2, last gen). I need the PC for games from Irrational, Blizzard, IO, Valve, Benoit Sokal, etc... (1st and 3rd person shooters, stealth-action, real time and turn-base strategy, adventure, etc.) I need a Nintendo console for the latest Zelda, Metroid, Mario, Smash Bros. installments (along with many other games on the platform that catch my attention). And the PS2 I need because there are a considerable handful of games that were really tough to miss out on (Silent Hill, MGS, GTA, Shadow of the Colossus, etc.)
Why choose a favorite when I get to play all those games? Like a good parent, I love all my children equally (but PC gets extra dessert tonight... and Wii has to sleep in the shed. I don't accept name-calling in my house).
"Whenever you find a man who says he doesn't believe in a real Right and Wrong, you will find the same man going back on this a moment later." -C.S. Lewis
"We all make choices... but in the end, our choices... make us." -Andrew Ryan, Bioshock
Prediction: Wii passes 360 in US between July - September 2008. (Wii supply will be the issue to watch, and barring any freak incidents between now and then as well.) - 6/5/08; Wow, came true even earlier. Wii is a monster.