Build/buy a computer for television: DVR, DVD, high-def, etc.

[pr0crast]

If you are ethically flexible, pledge to buy the DVDs when the show comes out (if you want) and then download the pirated DRM-free XVID versions of the shows after they air and play them on a networked dvd/xvid player (Snazzio makes a high def one for ~$300). This is a much more reasonable alternative to building a whole freaking rig to deal with all the ridiculous DRM formats that corporations are throwing at you.

And if you want a DVR, why not rent one from your cable company for $10/mo?

If you are really intent on this though, there are whole forums devoted to "home theatre PCs" that will no doubt yield much more helpful responses than 2p2. One place to start looking might be avsforum.com.