It feels...

naughty...

Seriously, though, so long as you have a good emulator (and with older games, it's pretty hard to find a bad one.), it'll be fine. I'd get a PS2 Conroller to USB Adapter, though. The PS2 controller generally works with any emulated system, and with some games, it's pretty hard to play with anything besides a Gamepad. At least, to me it is. Just out of curiosity, which systems besides the SNES are you planning on Emulating?