oooh... again favorites is tough, but lets see Super Mario Galaxy 2 definitely, xenoblade chronicles (even though ive never finished it) Wii sports resort slaps, and i have a soft spot for Goldeneye 007 for the wii (that was like my shooter that i played when friends came over) I already saidf twilight princess for gamecube, and i do enjoy skyward sword.
Also metroid prime trillogy was so great on the wii.