So, looking though peoples answers, people who buy these devices seem to be mainly consumers and not doers.
Probably why I don't see the point of them, I like everything I have to have a function. My phone gives me the portability I need away from the desk. I use it to be warned of important emails that need servicing, it gives me maps and navigation and music on the go.
I don't read books or watch films because I always feel I'm wasting my life away if I'm sitting and doing nothing. So if I want to see a film for leisure, I go to the Cinema. Who wants to watch a film on a 10" screen anyway?
One point to note, I really, really don't like touchscreens, I have to put up with it on my phone but no way would I purchase any other device with one, I hate the tactile greasy disgusting feel on my fingers, same with laptop touchpads.
If they released a tablet with a decent stylus input that is single pixel accurate, then I might feel different.