Pout

I'm kinda puzzled by setting up my pc-tv-audio in my new house

what i want / need:

* audio in all rooms (preferibly all from the same source, maybe able to select a subsource for each room)
in the living room there is a 5.1 sound system
* tv straight from the cable
* dvd straight to tv
* recording from tv on pc
* play from pc to tv (video-out graka?) with usage of the 5.1 system
* play audio from pc to speakers in the different rooms
* cable tv through pc for time shifting etc

Basically i can do all of this just with my pc but i don't want any processor intensive programs running when i want to work on my computer and my girlfriend wants to watch tv or a dvd

Someone knows how to set this up? if it is possible.
Maybe i need 2 coaxial cables? Maybe the audio source selection erquires a mixing table of any kind?
Thx in advance!!

Greetz
Pout

extra question: would it be easier to put everything (tv excepted) arround my pc? to centralize all cables etc? Or would it be easier to put everything arround my tv and just connect the tv to the pc?