I have a finicky Gamecube and 5 controllers, one is a little broken on the joystick. The Gamecube's finicky because it's not as good at reading disks, so I just use my Wii.
A few good games, imo, are SSB Melee, Sonic Adventure 2 Battle, and Gauntlet Legacy.
I was still surprised to see a Gamecube selling for $30 at Gamestop...