I've gotten little use out of my Wii, sadly. A lot of the games, like Cooking Mama and Wario Ware are much better if you have a crowd (and a few rounds of drinks...) to play.
Super Smash Brothers Brawl is a big winner, though my favorite is No More Heroes. Twilight Princess couldn't keep my attention long enough to keep playing it, and Metroid Prime 3 was a giant disappointment. It felt more like you're playing Halo than Metroid, honestly.