Build a HD HTPC w/ cable card?

I'm thinking about upgrading from my Tivo Series 2 to an XP MCE 2005 HTPC. Right now, I have a standard definition TV, but I'd like to get a HD TV--but I'm going to wait until MCE has cable HDTV support. I've heard that MCE is updating sometime this year to include HDTV cable support (is this true?). Will that be with cable card? And if so, is it possible to buy hardware that I can use to upgrade my DIY HTPC so I can receive HD through MCE with a cable card? Is it worthwhile to build now or should I wait?