It's hard to bet against Apple. The two things I admire most about the company are its ability to think holistically about business models (iPod + iTues, iPhone + the App store, iPad + iBookstore) and its willingness to keep innovating. Imagine how different it would have been if Apple stopped at the first generation iPod, or just rode the iPod for as long as it could. Its willingness to step out and enter into new categories is an important lesson for all companies.
Apple is certainly one of the five most innovative companies today. They make consumer friendly products that do new as well as old tasks (email etc) for consumers. They have been seemingly able to raise the bar continually.
If one is not risking failure, one is not making the movements that lead to innovation. For the most part, it looks like Apple got past most of the challenges they came across in the development of the iPad.