My favorite wii games
Zelda: Twilight Princess
Super Mario Galaxy
Super Mario Galaxy 2
Metroid Prime Trilogy
Okami
Mario Kart
Phantom Brave
Super Paper Mario
Fragile Dreams
New Super Mario Bros
Tales of Symphonia 2
Gamecube Games that you can (and should) play on a wii if you haven't before:
Legend of Zelda: Wind Waker (one of my favorites in the series)
Tales of Symphonia (one of my favorites in the series)
Skies of Arcadia
Baten Kaitos
Baten Kaitos Origins
Paper Mario: Thousand Year Door
The wii also has a ton of older N64, SNES, Genesis, and other platform games that are sweet.