I bought a Raspberry Pi a few months ago and love it. If it had more than 1G of RAM it could be a serious desktop replacement. I tried using it for several days as my only work + play computer. I found that Ruby and Clojure development with Emacs was fine but using IntelliJ was too slow. It supported my writing tools fine.
If you haven't played with a Pi yet, there are about 6 programming languages set up and lots of available projects for school kids to experiment with.