Frankly, I just don't care for how MS runs the marketplace. I refuse to patronize movies from it, as I can't own them. I really like Sony's idea for the PSN, which will also allow you to port the movies you buy to other devices (like the PSP).
Still, I'd rather just get the Blu-ray for a 1080p version of whatever film. I'm curious as to how they'll look when the UHD/SHV (Ultra High Definition / Super Hi-Vision) sets surface. Considering the difference in image from a 120 Hz set versus a 60 Hz, I'm sure they'll still look great, but I can't help but think that movies are going to be re-released in 2160p, and again in 4320p. This would be an excellent reason in why HD-DVD would not last as a format and Blu-ray would (both for storage and necessary bandwidth, though I'm not sure what the bandwidth requirements for a 4320p source would be - perhaps "the next thing" will be necessary by then).