Commodore's first computer that was specifically targeted at home users.
VIC-20 was technically pretty good machine at the time of its release (1980), and while Apple beat Commodore at speed when coming to the home market, VIC-20 still became popular due to one advantage: price. VIC-20 was cheap.
Of course, VIC seems such a bad computer nowadays, but it was something utterly amazing at its time. The basic model had 5 kilobytes of RAM (in BASIC, 3.5k usable) that could be expanded to 32k - pretty high! The sound capability was pretty good (primitive compared to C64, of course), graphics had resolution of 176x184 in graphics mode and text display was 22x23 characters! The processor was the legendary 6502.
Many people I know remember Atari 2600 with some nice phrases like "that thing was a piece of crap technically, but the games were damn good!"... for me, the same sensation comes from VIC-20. VIC-20 had some truly unforgettable games that just can't be easily replicated. Every time I hear those jolly melodies of Jupiter Lander, my depressions disappear. And for a longest time, Omega Race was remembered as the Greatest Game Ever - and is still believed to be one of the greatest games in the history of home computers. My first game I played on VIC-20 was Garden Wars.
Around 1984, Commodore started getting ready for new computer models VIC-10 (ill-fated Ultimax) and VIC-30 - released as Commodore 64. That, of course, became even bigger legend.