IBM System/360 mainframe (1964)
In the early 1960s, IBM bet the company on the 360, and ended up with a product line that more than any other popularized the use of computers in business. You can't beat the IBM System/360 mainframe for longevity -- some are still running. At the 40th birthday party for the 360 in 2004, Fred Brooks, who led the machine's development, credited its success to OS/360, "the first industrial-strength, 24/7 operating system." The 360 -- and its descendant the 370, introduced in 1970 -- so dominated the mainframe market that IBM and its competitors were referred to as "IBM and the Seven Dwarfs" (Burroughs, Control Data, General Electric, Honeywell, NCR, RCA, and UNIVAC).