The Gamecube was home to many great games that may have gotten overlooked because the system simply wasn't that popular. Since the Wii is backwards compatible many new gamers are now able check out these classic titles for very cheap. The following is my list of Gamecube titles you should definitely check out on Wii.
Especially VIEWTIFUL JOE 1 & 2 (not red hot rumble) :)
and zelda: WW