I use the Keyboard for Fighting games if I play on the PC, mostly using ASDF + the Arrow Keys, it's a little bit like using a arcade controller minus the Joystick.^^
I tried to play some Games with pad, but the Delay is to high or something, for example I can Perfom the Raging Demon on the Console with the Ps3 Pad without any problems, but if I try that with a Pad on the PC, than it never works for some reason, I have the same probleme with other Fighting Games, using a Pad on the Console works fine, but I get problems if I try the same on the PC.