R2 also had that computer interface thingy that he could plug into anything... all it ever did was spin... you'd think they'd have a better way for two computers to communicate other than a little spinny probe thing.
R2-D2...circular saw, fire extinguisher, jet propulsion (didn't he use it in ROTJ, or am I thinking of the new movies?), hologram projector, starship navigation, lightsaber ejector...what other features did he have?