When it comes to really feeling the retrones of a game, the atari 2600 with it's one button and long directional stick. Of course when it comes to games from the nes era to today, a modern joy pad like the PS3 controller (using motion joy to connect it to my PC) not only feel comfortable, but felt just right (had lots of trouble doing any street fighter moves with the snes controller before).
This thing though:
makes any retro game, including galaga much more fun to play.