I have a general purpose machine with Ubuntu installed. I use this as a media server using serviio and air video server. My Samsung LED TV, Xbox 360 and Ipad can all connect to this over my wifi network and stream movies directly. I also have a headless web based bittorrent client installed on this. (using tranmission). This allows me to download torrent files directly and they are instantly available on all my devices..
As well as that it serves as my source repository (subversion), fileshare, and apple time machine backup. Oh..... it also acts as VM host for all my dev images
