360 pad is my favorite controller of this gen. It has the best analog sticks, triggers, and rumble. The design also looks good. My complaint with the 360 pad, like everyone else, is the D-pad. Also, it's a bit hard to move from the bumper buttons to the triggers but that's understandable for a pad w/ bottom triggers.
WIImote: motion control feels good but buttons are too few and too small.
Sixaxis- Positives: basic Dualshock design. Negatives: terrible wireless functionality, weak motion control, worst triggers of all time, loose analog sticks, no rumble. Basically I'm glad that they're replacing the sixaxis with my favorite controller from last gen, the DS2.
Last gen-
1st) DS2 2)Xbox controller S 3)GC
DS2 had by far the best placement of shoulder buttons. EA big and action games worked better with the DS2 than any other controller.
The Xbox's controller S was very comfortable and the best sticks&triggers. However, the black and white buttons were pratically useless for any game that require quick use of them. Also, rumble felt very crude on the controller S compared to the DS2.
Gamecube controller was comfortable despite the funky look. However, the button placements make the controller practically unusable for many 3rd party games. I often used a PS2 adapter for 3rd party games instead.
Old School-
Genesis 6 button pad. I would probably have said the Saturn pad if I had a Saturn, since the Saturn pad is just a refined version of the Genesis pad.