From what i've seen... It's tech mad people who want tablets. They can see situations where a tablet will be easier than a laptop/netbook, like in a car or a quick visit to show off your latest holiday photos to granny.
Okay so there is also a fashion accessory race (or fad) going too, else people would still be using boxy looking phones and computers.
Let's see how they evolve, the engineers/designers might get creative with them.
I imagine kids will still do their computer classes on desktops, but as a general learning aid they will likely use pads, which is pretty cool, no textbooks etc.