I believe it's Thomas Kuhn who gave us the notion of "Paradigm Shift" as a way to understand scientific revolutions. You know, stuff like going from thinking that the universe revolves around the Earth, to thinking that it revolves around the Sun, to thinking that it don't revolve around nothing.
It all works very well until you start looking at what individuals thought and did. Then it ends up being pretty hard to figure who does what.

But another "paradigm" is a usage paradigm, and, if there is a shift, we're in the middle of it.

Think of the calculator. For many people, the first electronic computer to enter their home was a calculator. Very few people use the calculator regularly as ends in themselves. They use them aside papers with figures, or sometimes to run up numbers in a conversation, or whatever: the calculator plays a support role in a number of tasks.

Now, think of the Personal Computer. Back before multitasking, you'd run a program; you'd sit at the computer, and you'd operate it.
With multitasking, we do the same thing, but we're bombarded from several different directions with things that require our full attention. (office tasks, programming, games)

Computing power has grown considerably, so we can also run "passive attention" stuff (music, movies, television): once we set it on the way, we can pay attention to it without continuous interaction. This class of tasks ("lean out" computing, as opposed to the "lean in" of the first class) has spawned dedicated computers for media centers, and personal media players.

Where do these Internet Tablet Things fit in? Back at the calculator. They do the things that require a computer to play a supporting role. And companies are converging on this group, trying to hit the home run: Asus with their Eee PC, any number of companies with Intel UMPCs and a Tablet edition of Windows, and Nokia.

But I've said all this before. How it applies to Apple vs Nokia is: frankly, I don't care. Apple I'm sure puts out a fine product, and iPhone/iTouch owners should be very proud. I'm also very aware of the limitations of the n800 I pack around (and constantly recharge). But, for its shortcomings, it not only fills my needs, I find uses for it I hadn't imagined. A stylish web browser attached to a media player would not meet my requirements. That's not even in the class of devices I need.