NFS Carbon! Although I hate the fact that cops take 5 minutes to avoid, but only because there's always one more, not because they're any smart. But Wii Sports is a good game as well, even though Boxing (which I enjoy) is sometimes a little to unresponsive for me.
But I reckon that the best game for the Wii will for Super Smash Brothers: Brawl. Unfortunately, it's been delayed....