I am not a huge SSBB player, but I played just fine with only wiimote+nunchuk.
If you want 4 players then get Wii Sports + 2 more wiimotes and 3 nunchuks.
IF you want a gc controller, definitely try to get the wavebirds. They are by far better. You will probably want 2 classic controllers if you plan on playing vc games that are not just NES.