IBM (1981)
Product shot of IBM Personal Computer (5150), introduced in 1981;
Features: monitor, keyboard, and pin-feed printer; b/w.The operating system (OS) was by Microsoft, who licensed it to IBM as PC-DOS.
Although not necessarily the best machine by technological standards, IBM's expertise and the fact that the IBM PC actually looks and feels like a professional computer system made the IBM PC and the numerous PC clones extremely popular. They have evolved into today's so-called Wintel (Windows + Intel) computer systems, used world-wide.
From http://www.blinkenlights.com/pc.shtml