Sony Walkman TPS-L2 (1979

Portable music players are so cheap and ubiquitous today that it's hard to remember when they were luxury items, widely coveted and often stolen. But when the blue and silver Walkman debuted in 1979, no one had ever seen anything quite like it. The $200 player virtually invented the concept of "personal electronics."

The first Walkman (also branded as the Stowaway, the Soundabout, and the Freestyle before the current name stuck) featured a cassette player and the world's first lightweight headphones. Apparently fearful that consumers would consider the Walkman too antisocial, Sony built the first units with two headphone jacks so you could share music with a friend. The company later dropped this feature. Now, more than 25 years and some 330 million units later, nobody wonders why you're walking down the street with headphones on. Learn more in Sony's history of the Walkman. PCW photo by Rick Rizner; Walkman courtesy of Melissa Perenson.