If I were single and didn't think about the future as much, I'd probably own stand alone HD-DVD AND Blu Ray players and buy even more movies than I do now.
But I'm not. I have to limit my purchases somehow, and going out and getting another player to play a whole other set of movies is just too much for me. Hell, if the PS3 didn't have a built in Blu Ray player, I'd have zero interest in the format war.