I don't think the blu-ray/hd-dvd formats are useless at all. They're just giving us a media format that outputs the same resolution as the latest TVs and it's a big increase in quality. Don't rebuy your movies, just buy new movies (and maybe re-buy your favorite movies) on these new formats when the price of the players come down to an acceptable level.
I think watching the HD-DVD of Grand Prix justified my HD-A1.