There shouldn't be in the long run, tho there has been in the short run in favor of HD DVD. But it's still early days, and BR authoring seems to be catching up.
I agree with this. I have both the PS3 and the Xbox 360 HD DVD add-on. I had both hooked up to the same TV for a short time (my beautiful plasma) and think that the reliance on mpeg 2 by Sony has hurt it in the short term. With the VC-1 encoded movies, the plasma showed in insane amount of subtle blacks and shadows. With a couple of the Blu-ray that I've watched, I've seen what would appear to be some crazy black crush.
That said, Shifty's got it right. The PS3 is worth it just for the Blu-ray capabilities. It's a gorgeous piece of electronics and makes barely a sound as it plays. It's DVD playback is decent. And, of course, you get the other benefits of the PS3. However, the lack of an IR port is, umm, annoying.
With the HD DVD player, you get an excellent HD DVD player and an above average DVD player (especially if you have a VGA input into your TV, since you can upscale to 1080p then, if that matters). As well, I happen to like the "dongle" approach, since now my 360 only ever has games in it, while the add-on only has movies. The PS3 requires me to swap them out. this is obviously a minor point.
Finally, from all the rumblings I've heard, combo-players will be coming out within the year, so any movies you buy should not become obsolete.
All that said, I'm still not sold completely on either format. The biggest selling point to me so far isn't the increased resolution, but the increased color accuracy. Anytime I play a SD DVD now, they look washed out. But after sampling both formats in-house, I'm willing to put money down that in a test between a very good encoded SD DVD and HD DVD or Blu-ray, most people wouldn't detect the difference.
So, in the end, I would suggest that unless you have other reasons to pick up a Blu-ray or HD DVD player (such as for the PS3 or Xbox), then I'm not sure either are terribly compelling right now...
EDIT: One other thing: It should be obvious by now that the disc capacity issue is a non-factor in movie playback quality. Quality of the codec and capability of the compressionists have more to do with it than anything, both of which are effectively format neutral.