Now might be a good time to mention that I've been out of the pc game for so long that I was just planning on shoving vista on there and using media centre. (....more)
First time around, I found MythTV too daunting. Too many pieces. More recently, using one of the tailored distros (MythDora) installation was much easier. Anyhow, if you are curious about that, it would probably only take about 30 minutes of your time to install MythDora before you go on to wipe it and install Vista....and activate it....and ....:)
http://www.mythdorawiki.com/wiki/index.php/Main_Page