Farewell C-3PO, we hardly knew you.

The world's most popular service robot (that is, not one that is in a factory) looks like an enormous ice hockey puck and vacuums your carpets.

The Roomba, made by iRobot, doesn't look anything like any of science fiction's robots, dating from their inception by Karel Čapek in his 1920 play R.U.R. (Rossum's...