Well, tablets are going to become a new "screen" in our lives, much as the iPod created a space for music players and the iPhone did for smart phones. As with those other things, Apple won't have the only tablet in town. This device moves us much further down the path of ubiquitous computing--you will have several of these tablets lying around the house. It doesn't matter which device you choose, you'll still be able to access your various needs--documents, email--on the internet cloud. Reserve a movie? Check. Weather? Check. Newspapers; magazines. You will never go far without some sort of computing device near you.
Yet, at the same time that computing envelops our lives, computers will become more transparent and invisible than ever. This is the same transition that cars went through. When cars first came out, you basically had to be a mechanic to use one. Now, everyone drives cars without thinking too much about it. Cars themselves have become much more advanced, but they've become steadily easier to operate. If you really want, you can still tinker with them; but that's mostly a preserve of specialists.
The computer, too, is seeing a transition in which more and more of its functions are going "under the hood" to make it easier for the end user; while things get ever more complicated on the back end. To hear fanboys complain about this is a bit like hearing gearheads complain about how people use automatic transitions.
This gets us to a point where even a baby can navigate an iPhone. This raises some interesting questions. We also know chimps and some other animals are about as intelligent as babies. Can chimps use iPhones and iPads? Would they ever have any desire to take and share photographs of each other? Would this ever go anywhere?