I'm of the opinion that most PC pads suck compared to their console brethren. Because of this, I have adapters for most all modern controllers.
The Magic Box (mentioned above) does Saturn, PS2, and DC controllers. Right stick works just fine for me, but there is no rumble support.
The XBox/USB adapter works great and supports right stick AND rumble.  Get a controller-S and this adapter and you'll have a damn fine gamepad for your PC.
The GC/USB adapter works well too and supports rumble and the C stick. 
I also own a couple of Sidewinder Classic gamepads (15 pin, not the crappy USB versions). These were great for fighters due to the 3x3 button placement, but the magic box-> Saturn controllers pretty much made these useless. I still hang onto them though.