PC World’s list of the top tech gadgets of the last half century, rated by “usefulness, design, degree of innovation, and influence on subsequent gadgets, as well the ‘cool factor,'” includes Sony Walkman (1979), Apple iPod (2001), and a tie between ReplayTV RTV2001 and TiVo HDR110 (1999) — the top three.

Other cool items include iRobot Roomba Intelligent Floorvac (2002), Sharp Wizard OZ-7000 (1989), and MITS Altair 8800 (1975).