if you are looking for console emulation, a modded xbox is a great choice. the gamepad has enough buttons to handle jsut about every console emulator that runs on it. it is how i do all of my classic console emulation. it works great with NES, SNES, GEnesis, Turbografx 16, pretty well with N64, and some playstation games. plus it is easy to connect to your big screen tv and play from the couch with a gamepad, just like you used to with all of those consoles you are trying to emulate...
to top if of, you can pick up a refurb xbox for $40 at gamestop now, so it is very cost effective