The Hotrod is fantastic for the vast majority of arcade games I play. I even managed to get it working on my xbox with some black magic, but it only works for one player.

The Sidewinder was my controller of choice for years for console emulation, I even bought a couple extra to daisy chain when I found a guy at a computer fair selling them for $5 a pop. I avoided the usb ones since they had a reputation of having a wretched d-pad, but I've read a few reviews of later usb models that had a better pad.

Some of the recent console ports to pc had me wanting a dual analog controller for them. I think one of the Saitek pads would actually be a better general purpose controller for emulation since it has 6 face buttons and 4 triggers, but I already had a couple 360 controllers. They're great for console ports, but I don't like them for emulators. The d-pad ranks right up there with the PSP one in terms of crapiness and there are only 4 face buttons. The MS drivers for the 360 controller are also pretty suck-tastic and extremely basic. You can use the XBCD drivers instead, which are FAR better, but they only work for the wired 360 pads. And no, you can't convert your wireless pad into a wired one with a play and charge kit :(