Not to mention you can play with a PS3 or an XBOX 360 controller without even having to buy anything.
Also, yes I used to have that adapter to plug in a snes controller into a usb port. Cost me like 2 bucks. Although it doesn't have enough buttons for N64 games. But I play all my emulated games on a PS3 controller. It's layout is similar enough to play SNES games, but with enough buttons to play n64 games.