Wii controller. Hands down. Or... rather, "hands down".
Oh wait. Those are wireless. Rats.
I gotta put a vote in for the Flightsticks. Some of ours wobble too much now, so we just swap them out for ones that don't.
Now, if I could hook up my Microsoft Sidewinder Precision Pro, with 3 axis of movement, a throttle and an armada of buttons, and a game port plug to boot, Mecanum drive could be a lot easier.......