1. Intel 4004 (1971)
Breakthrough application: Busicom 141-PF Calculator (1971)
What microprocessor could be more influential than the first commercial model of all time? The 4004 was a 4-bit processor designed specifically for Busicom desktop calculators. It proved that a potentially wider market for microprocessors existed, and it led Intel--then a memory-chip manufacturer in search of a calling--to its true destiny, that of a microprocessor innovator and a trendsetter for decades to come.
Photos: Dentaku Museum, Intel