I use the GameCube controllers. I'm not sure why, but my parents bought a 2nd GameCube. You guys are going to totally LOL. I have 6 controllers. 2 are from when I got my first GameCube for Christmas the year of it's release (one was packaged, and the other was the one that my parents bought separately so my friends could play when they came over). Then, my mom saw them at Walmart for $7.00 each, so she bought a third. Then my parents bought the 2nd GameCube for no apparent reason, and it came with a 4th controller. Then, we got 1 more GameCube controller for the 2nd GameCube, and my brother saw a used one at GameStop for like $5.00 so he bought it. Guess what; the first 2 GameCube controllers I've ever had are the ones that are in the best shape. Following that, there's the 6th one (the $5.00 one at GameStop), the Walmart one which has a loose control-stick, and the others have no grip on the control-stick.
The only reason I use the GameCube controller is because I'm comfortable with it. My friends bought Brawl, but they had never bought Melee because they don't have GameCubes, so they use the Nunchuck/Wiimote combination. One other friend of mine uses the Classic controller because he had a N64 and Super Smash Bros., but he decided to get a PS2 instead of a GameCube during that "generation" of gaming. So he's used to the N64 controller.