I don't have a HTPC. I do have a Crestron control system and a iMerge digital music server, so I am not pushing for a HTPC anytime soon.
But, I do want one at some point and I see the HTPC becoming the true core of the home theater system. This absolutely MUST go hand in hand with CableCard, DishCard, and DirecTVCard. That is, I still watch 90% television and the rest movies and you better believe that if I am going to invest in a HTPC I want more than music, video downloads, and DVDs. I've already GOT all that! It is integrating it with my normal cable viewing and HDTV with time shifting capabilities that is what I consider most vital. Being able to record my HBO-HD, and ESPN-HD as well as the other digital cables... forget that analog garbage.
Yes, I saw... what was it - Niveus? at CEDIA... That's a lot closer to what I'm talking about, but of course, theirs crashed twice during our viewing of it... So it's GOT to be reliable!