Riding on the coattails of the 51GB HD DVD announcement
was the approval of the dual-layer DVD / HD DVD combo disc format. These combo discs have been a feature of a several releases, but the linked article provides a good analysis of serious challenges the format faces. The bottom line is this -- for almost everyone, one of those sides goes largely unused. If you have a HD DVD player, the DVD side will only see duty in secondary applications. And if you don't have a HD DVD player, that HD side isn't going to see any use at all. And with the format war, average consumers don't value future compatibility. This wouldn't be a significant issue if there were no additional cost associated with the combo disc. But there is
, and that kills the deal. There's plenty more to the critique, so check out the link if you're inclined.EDIT:
The 51GB HD DVD approval included the single sided combo format, not the dual-sided one currently used in several releases. - Thanks, Kevin!