Check out the news from Apple:
http://articles.moneycentral.msn.com...boutApple.aspx
HD movie rentals through AppleTV. Supported by ALL of the major movie studios. I'm sure that HD purchases are not far behind. Gates touched on getting rid of physical medium as the future focus in a recent discussion as well.
It seems to me that Bluray and HD-DVD are just a temporary "stop" in the HD video journey.