The Wii remote is like a Nintendo 64 controller (middle and right stick) except separated. It was an okay transition for me because it was really similar to the N64 contorller (no thumbstick in right hand).
IMO, Xbox 360 controller is the best; concave thumbsticks are really comfortable, and the flipped D-pad and thumbstick for left hand (PS controllers have D-pad closer to to left side instead of the middle) is extremely useful; I can call a UAV by reaching over with my right thumb while still running around with my left in MW2.
Once again though, it’s all based on style of gameplay;
By the way, for you PS3 owners out there, is there button sensitivity on your controllers? (Like in DOA3, pressing lightly and pressing hard on buttons have different actions for Xbox)