I can certainly see a day when tablet or phone form computers are the center of the personal computing experience. With the maturation of the personal area network, there's no reason to believe a bluetooth enabled computer could not automatically pair with nearby peripherals so that my portable computer outputs to nearby displays, accepts input from local keyboards and mice, and logs onto designated networks. This is not science fiction. No reason why a touch screen could not be so paired.
I suspect this is the vision for the surface devices.