Just wanted to point out that currently Blu-Ray DVD movies are discs that actually have less capacity than the HD-DVD discs. HD Blud-Ray movies are on 25GB discs and HD-DVD are on 30GB discs. This is, most likely, due to the low yield rates on double layer Blu-Ray, which (in addition to the greater expense) makes them less desirable than the smaller single layer discs. Another reason is that both formats are more than ample for HD movies which seem to be coming in at around 6GB per hour of HD media. This means that even with the smaller capacity discs The Lord of the Rings could fit each movie on a single disc with a second for the extras (same with HD-DVD).
I don't think capacity will have any impact on which format wins the movie war since both are more than ample for that need. The deciding factor will be the installed base. Sony having signed more studios is an issue, but if HD-DVD pulls ahead those studios will abandon Sony in a heartbeat because they're fickle and are looking at their own profits without any regard for Sony. Right now (not including the PS3) the installed base for HD-DVD is far greater than that for Blu-Ray, but the numbers we're talking about are small to begin with (ie. sure 2 is twice the size of 1, but the actual numbers are small).
Blu-Ray will win on the PC because capacity is a very important there and the much higher cost of discs is a small issue for end users who aren't looking at the profit margin of one million Blu-Ray versus the profit margin of one million HD-DVD.
It's still very much in the air and it is with the movies that one format or the other will have a win, not with games or PC storage. Either way, however, we as consumers are losers in this war. Until there is a clear winner any money we spend could easily be entirely wasted, and I don't know about you, but a grand wasted is an awful lot of money for me. I believe that this is a lot of money for most people and they will wait, even if it's a couple of years, for a clear winner before spending their money.
Either way, between two and five years from now people will begin buying one or the other for $150-$200 for a player and $12-$25 for each movie no matter which format wins.
Check out Home Theater Blog's entries on myths of Blu-Ray and HD-DVD and his pick in the format war.