Probably someone already spoke about this here, but I really find it interesting and I'm trying to imagine how MorphOS (that is surely lighter than Linux) could run on it..

http://www.youtube.com/watch?v=6BbufUp_HNs
http://www.youtube.com/watch?v=HGcILQ4WxEk&feature=related
http://www.youtube.com/watch?v=e_mDuJuvZjI

http://www.raspberrypi.org/

Thi kind of hardware would be perfect for set top boxes, mediacenter, carputers, etc..