It sounds like this is the type of system that your are looking for.

This is the windows based version of an open source media server system: (I don't have any experience with it I have just read about it.)
http://www.team-mediaportal.com/about_mediaportal.html

This is a Linux based version of an open source media server system:
http://www.mythtv.org/

I have the mythtv version running at my house. You have to be fairly computer savvy to use it. A friend of mine who is a programmer put it together for me so I could be a tester for him. The nice part about it is that each TV only needs a client box that is connected to the network via CAT-5. It gives you the ability to watch saved television programs from any television in the system.