I would say use either the gamecube controller, or the classic controller. The wiimote may be difficult to use first of all, so practice with it offline, and use the gamecube controller online.
I hate using the analog stick so the WM+N and Classic are out for me, I don't have a GC control, so i been using the just the wiimote...... is not bad, I just need more time to get used to it.
WM is aweful! It's hard to press A+B and the - and + are very far away, and SSBB requires fast movements and thinking, so you will be probably pausing the game by accident half the time.