13. HD Radio (2003-?)

HD Radio was supposed to be the next great thing in "free" radio, offering clear, digital "CD-quality sound" and more listening choices. But it's been slowed by the manufacturing costs of both the HD Radio chips and the radios themselves--as well as poor marketing. This year, the prices for HD Radios have come down considerably--note the Sony XDR-F1HD and portable Insignia NS-HD01--giving hope to backers and fans that the technology will find more success next decade.