Sony CDP-101 (1982)

The first commercial compact disc player signaled a technological sea change that ultimately caused millions of music lovers to ditch their turntables. The boxy CDP-101 wasn't especially sleek, and at $900 it was priced for audiophiles, but it ushered in the age of digital sound--no more hisses, scratches, pops, or skips. Now, with SuperAudio CD and DVD-Audio offering vastly superior sound, and MP3 downloads dominating music sales, CD players may eventually join turntables and 8-track machines (#46) as relics of our audio past. But they will sure have sounded good while they lasted.

PalmPilot 1000 (1996)

The PalmPilot 1000 was everything the Apple Newton MessagePad (#28) wanted to be: a "personal data assistant" small enough to fit in your shirt pocket, with enough RAM (128KB) to hold a then-impressive 500 names and addresses. The handwriting recognition actually worked (once you mastered the arcane Graffiti software), and best of all, you could sync your data with a PC or Mac desktop application. The brilliance of the Palm concept was its recognition that people wanted a supplement to their computers, not a substitute. Subsequent models grew smaller and more powerful, but were basically refinements to the original PalmPilot's elegant simplicity.

(Tie) ReplayTV RTV2001 and TiVo HDR110 (1999)

The appearance of the first ReplayTV and TiVo models--the pioneering Gemini of digital video recording--in the number three spot on our list may be a measure of how much we all hate TV commercials. The concept is simple: Digitize the TV signal and stream it to an internal hard drive, so the user can pause, rewind, fast-forward, or record programs at will. For the first time, users flummoxed by their VCRs (#29) could record an entire season of shows with a few clicks of the remote. And yes, it may be cheating to count these two products as one, but they appeared at virtually the same time, and each brought different yet important strengths to the DVR table. TiVo undoubtedly won the brand-recognition competition: When Janet Jackson suffered her infamous "wardrobe malfunction" at the 2004 Super Bowl, thousands of viewers "TiVo'd it"--over and over and over. ReplayTV, on the other hand, was more aggressive with commercial-skipping and networking features. In any event, the success of these products may be their undoing, as digital video recorders become a standard feature of cable and satellite set-top boxes. Eric W. Lund has more than you'd probably want to know about earlier models of both. PCW photo by Rick Rizner.

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.