I just read a blog entry about „touch screens not taking over„. True, you do not want to touch the screen on your writing desk behind the keyboard. Neither it is easy to reach, nor do you want to speck it with finger tracks. But that is not the point.
I am using a 16×10 screen, a separate keyboard, and a cordless mouse at home and in my office, which I dock with the laptop I carry between the places. I do rarely use my laptop elsewhere. It is too large for pleasant couch surfing. For slides in classes, I use a netbook with much less weight. For the train or the hotel, I use an Android tablet to read on. For me, serious work cannot be done on a small device anyway.
Now imagine a tablet PC, which docks just like my computer, can be used casually like a tablet, and has a HDMI output for a beamer or a TV. Imagine a small packaged emergency keyboard along with it. And soon you arrive at something like the Surface Pro. I need a bit more power and an easier dock. But Microsoft is on the right track, I think.