Anonymous left a comment pointing me to what appears to be some really nice software: MediaPortal. Unlike GB-PVR and MCE 2005, this one is completely open source so if I had the inclination I could modify/add anything to the app. Before I left for the dealership I downloaded the app to my laptop; and I kept myself occupied for a few minutes by giving it a test-run without any of the neccesary hardware.
It is nice to see that it caught me and helpfully notified me that I didn’t have several things installed, notable an MPEG2 decoder, FFDShow (whatever that is used for), nor VobSub (used to provide subtitles…ahh, memories).
I think I may have to turn my old PC into a guinea pig for the various HTPC software out there to see which one I like the best. I do plan on using MCE2005 qualified hardware so compatibility shouldn’t be a problem there.