While so basic you sort of don't even want to refer to it as a robot, the Roomba does the one thing we always eventually want out of a robot--it cleans up after us. For the uninitiated, Roomba is a 13" disc-shaped vacuum that rolls around a room and cleans the floors, finding its way around with only an infrared sensor and a sense for "virtual walls" to guide it. Simply put: it's popular, and it works. (Check out the wet/dry Scooba while you're at it.)
