Hm, the reaction to this thread has made me consider my own Wii collection.
I have 17 retail Wii games. Of those, 12 are exclusive. Of those exclusives, 5 are third party games. To name them, Blast Works, Boom Blox, No More Heroes, Trauma Center: New Blood, and Zack & Wiki.
So Microsoft has a chance to steal about 30% of my games collection for the 360. That's not bad at all. And things will swing even more to third party exclusives in the near future, since de Blob, Samba de Amigo, Sam & Max and Deadly Creatures are the games I'm most interested in owning before the year is out, not to mention '09 releases.

"The worst part about these reviews is they are [subjective]--and their scores often depend on how drunk you got the media at a Street Fighter event." — Mona Hamilton, Capcom Senior VP of Marketing
*Image indefinitely borrowed from BrainBoxLtd without his consent.