Don't knock it 'til you try it. The Saturn 3D "pancake" controller is actually pretty comfortable (especially if you have huge hands like me), and it has an awesome analog stick. If anything, the worst controller for the Saturn is the original one that the American consoles launched with. The shoulder buttons didn't respond... oh, about 90% of the time.

Anyway, I'd have to go with the Atari 5200 controller. Unresponsive buttons, awkward layout, a terrible analog stick, and they broke. A LOT. As in, I've never seen a fully functioning one, ever. 

I think that either the dreamcast controller or the xbox controller being the worst of all time! No wonder MS redesigned the controller after all the hand injuries j/k :D

I didn't care to much for the original Xbox controller, not as bad as the dreamcast in my opinion, but man it was heavy and I HATED those two other buttons LOL. And what was with that HUGE FRICKIN LOGO in the center of the damn controller xD

CDi, I actually like my controller to effect the game im playing. Im sorry but 1991 wasnt a good time to develop a wireless controller

For regular controller I´d say it was the original PS one... sorry but I just never liked it... so small and painfull. 

I always hated the Playstation controllers. Why the D-Pad is on the main position? And why it's... cut in four? It causes me blisters. I don't get it. Also, the analog sticks are not exactly precise or comfortable. They're too lose. Not to mention the button-naming tradition. Triangle?

The Xbox's Duke gets a honorable mention too.

Worst controllers ever

 <

No such thing. I like all controllers. I like the Atari 5200 controller, the Atari Jaguar controller... I really don't have a problem with any controller.

bad controllers? whiners^^ , every controller can be mastered

Good:
Xbox 360
N64 (crap at fighting tho)
Snes
Gamecube
Wii
xbox

Average:
ps1/ps2/ps3 (poor at FPS)
dreamcast
Genesis
NES

Poor:
Jaguar
3DO
xbox (original)