Any PS3 arcade stick will work as a standard USB device on OS X and Windows. If you don't want to get a arcade stick, you can get the PS3 SF4 controllers. They look like a Genesis 6-Button controller.
While true, if its for SF4, a 360 controller isn't the best idea as the D-Pad is not very well-made and its much cheaper to buy a $20 Logitech controller then a $50 Wired 360 controller.