$25 PC - Delicious Raspberry Pi
Taking the cost of computing down to the cost of a textbook is the plan for the Raspberry Pi Foundation. This is not just an educational tool for developing countries like what the OLPC project is doing, it is a platform for discovery and experimentation in the developed world as well. Think of it this way: Do you want little Johnny taking apart the home computer that houses your tax returns which you never backup? Or would you rather plunk down $25 for a computer that he can experiment with that can integrate with old CRT TV's that you were going to recycle anyways? Oh, and it can run Linux, which is awesome.
(Picture from Raspberry Pi Blog)