HowStuffWorks has an interesting article describing methods of "printing computers". Now you'd think at first this is simply printing out the semiconductor chips, but the article describes how MIT and others are attempting to use 3D printing to print the rest of the computer as well! So far MIT has managed to print thermal actuators, linear drive motors and microelectromechanical systems. No, it's not yet enough to print off all the pieces of a computer, but clearly progress is being made.
And of course, the computer case is easily printed!