Steve Jobs seemed to anticipate the demand for the iPod from the get-go: "Music's a part of everyone's life," Jobs said at the 2001 launch event. "Music's been around forever. This is not a speculative market. And because it's a part of everyone's life, it's a very large target market all around the world."

As it did with the iPod, Apple didn't create a new product category with 2007's iPhone introduction. Smartphones existed before Apple came out with its effort, with existing devices aimed largely at business customers who wanted to check their email when they were out and about. Apple instead set its sights on the broader consumer market. It would appeal to the end user by informing its device with the same sensibilities it had used in the Mac: good design, ease of use, and a harmonious marriage between software and hardware.

"Every once in a while a revolutionary product comes along that changes everything," Jobs said at the 2007 Macworld Expo keynote when he pulled the first iPhone out of his pants pocket. "One is very fortunate if you get to work on just one of these in your career. Apple's been very fortunate. It's been able to introduce a few of these into the world."

That may sound like the kind of "reality distortion field"-style hype that Jobs became famous for--and to some extent, it is. But it also happens to be true. Look no further than how other smartphone makers responded--with devices that mirrored the iPhone's touch-screen controls, powerful Web browser, and array of third-party mobile apps. Where once every smartphone had to have a physical keyboard, many now rely upon just a touchscreen; that's a direct result of the iPhone's influence.

Jobs closes out his tenure as Apple's CEO by leading the company into what's being billed as the "post-PC" era--a period in which mobile devices no longer need sync up with computers. It was with that vision in mind that Apple rolled out the iPad, which brings PC-style computing into a handheld device. Launched less than two years ago, the iPad has already carved out a new market for tablet computing, with other companies once again trying to keep pace with Apple. It also joins the original Mac, the iPod, and the iPhone among the revolutionary products Jobs helped develop during his Apple career.