2007: Apple iPhone
Portable music players, camera phones, game machines, computers, GPS navigators, PDAs and even smartphones all existed before 2007, but you'd never have guessed it from the lines outside the Apple store when 4GB and 8GB iPhones first went on sale. Sure, people griped at the $600 price tag, and the cost of the monthly AT&T phone/data service. But you couldn't hear them over the sound of iTunes playlists and streaming YouTube videos.
Instantly hailed as revolutionary, the iPhone's gesture-sensitive touch interface and app store model set the standard for the wave of smartphones to come. Four and a half years and four models later, it's still the phone to beat and accounts for more than half of Apple's revenue.