6. Zilog Z80 (1976)
Breakthrough application: Radio Shack TRS-80 Model I
The 8-bit Z80 started out as an enhanced clone of the popular Intel 8080 CPU; but because the Z80 had better features for a lower price, it soon eclipsed the 8080’s popularity.
The Z80, teamed with the CP/M operating system, became the first multivendor computing standard. Much like Windows and x86 processors today, the CP/M-Z80 combo powered hundreds of business-computer models in the late 1970s and early 80s, perhaps the most popular of which was the "Trash-80."
Like many processors, the Z80 has enjoyed a rich second life as an embedded processor in consumer electronics, powering the Nintendo Game Boy, the Sega Master System, and other game consoles, as well as many Texas Instruments graphing calculators. Modern versions of the original 8-bit Z80 are still sold for embedded applications, making it one of the microprocessors with the longest continuous history of production.
Photos: Steven Stengel, CPU-World.com