Watching TV on PC - and Recording it?

Windows 7 came out in October, so I've been seeking a new PC.

I come up with an idea of throwing my old TV monitor, and include TV functions onto a new PC. I thought so, because Windows 7's Windows Media Center integrates with TV captions well. Less space to take monitors, less plugs to use, simply "nice".

So new PC goes like this

* PC stays up and running on 24/7 basic.
* PC functions "as is" when I'm working.
* PC turns into "Windows Media Center" when I'm not working.

Therefore, New PC needs to be quiet.

I am sure some of folks look into this. As a jazz lover who occasionally can't watch a programme on time, it will be nice if everything fits well.

Right, time for grabing quotes from shops then.