I made a full arcade machine also known as a mame machine
http://www.natesalerno.com/arcade.html
for yours you can use mamewah a frontend program to manage your emulators and games. A nice little touch is to make it so the frontend starts up, when the PC starts up. So anyone that isn't great with a computer can pick it up and play.
Gravis makes some nice USB game controllers. I like the ones that look like old Playstation\SNES controllers