I am involved in a great Open Source Project called Amahi Home Server
http://www.amahi.org . It has a lot of features ready to go out of the box, and a burgeoning one click install App Gallery that includes such media-centric apps as DLNA Server, Squeezebox Server, Amahitunes (a DAAP/iTunes server), Jinzora, and even MythTV backend is in testing. As a long time taper, I think its a great solution for media storage and streaming to your network. It is based on Fedora, with an Ubuntu version in development. I encourage everyone to check it out, and feel free to stop by the IRC Channel
http://talk.amahi.org or #amahi on irc.freenode.net with any questions. I go by the same username there.
Thanks,
Pat