I hope that Sony keeps the same design. It pretty good, although I would not mind if they switched the left analog stick and the D-pad.
Microsoft should slim down their pad a bit, and make the black and white buttons triggers simular to the L1 R1 on the PS2 controller.
I believe that Nintendo's controller is a mess. The D-pad is way to small, it should have a left and right Z button, the C stick is really bad for constant use(such as with a first person shooter), the left analog stick seems to be low quality(it comes loose quickly, unlike Sony's and Microsoft's analog sticks), and the ABXY buttons need to be in the SNES/PSX button setup. And would a select button really kill them. It could be mapped to a commonly used pause menu for most games, while the start button could take you to the basic pause menu, or the last menu you were at.