I think I'll make an effort to use the classic controller. Not only is about every controller going to wear out sometime, but eventually they are going to stop making GC controllers.
I wouldn't be able to stand the Wiimote alone. The D-pad just sucks because of the lack of pressure sensitivity. It will be incredibly hard to do up-tilts without jumping first, and tapping twice to run puts you at a disadvantage. I guess you could disable the tap jump but then you'd have to find another button, and you are already low on button room. Also, I really don't like how you have to take your hand off of the D-pad in order to hit A.
Nunchuk is okay, but I think it still lacks button room (or at least it looks like it would be a little bit harder to do certain button combinations, but then I guess you would just get used to it...), and more importantly, there is no C-stick on this one. I loved the C-stick in Melee and there are only a few modifications in Brawl but it is still worth having, I'll bet.
The classic controller has it all. The buttons are close together and it has two joysticks (one for pressure sensitive movement and one for C-sticking). The only thing I don't really like about this one is that the buttons are a little bit small and a bit spaced out, and I kinda liked how the left joystick was on the top of the left side of the GC controller.
Here's a picture of the classic controller.