My own vision of the future is an entirely modular computer system that is cumulative. That is, the computer begins with a small module about the size of a cell phone. By itself it can perform a bunch of functions.
Add a second, different type of module to it, and it becomes much more powerful, and able to do many other things. As you keep adding different modules, it becomes more and more functional.
The group of modules can also to some extent work while physically apart from each other, via Wifi, or plug into ever larger systems, such as cars, business mainframes, whatever.
You mean like this?
Game developer David Braben creates a USB stick PC for $25
-PJ