We can't have a list of early 80s computer ads without including the original IBM PC, the 5150. Released in 1981, Big Blue began running a series of print advertisements the following year for the 5150 -- as well as other IBM products -- featuring a Charlie Chaplin lookalike doing his best impression of Chaplin's most famous character, "The Tramp."
The 5150 was no tramp, however. IBM's original PC, which started at $1,565, featured a 4.77MHz Intel processor and a minimum of 16KB of RAM. Entry-level versions came with just a tape cassette drive and Microsoft BASIC, while more expensive versions featured dual 5.25-inch disk drives and IBM's PC DOS operating system, as well as a black-and-green display. The IBM 5150, which was eventually discontinued in 1987, is credited with popularizing the PC.