Kotaku blogged the Xbox 360 briefing at the Tokyo Game Show, and reports that "Now, HD DVD player. If it is connect vis USB cable, you can view HD DVD via your console. It looks 6 times better. It is full HD DVD 1080p." It will go on sale on November 22 for 20,790 yen inc tax -- £94 or $176, which sounds rather low.
Of course, as with Blu-ray, if there are no HD-DVD movies you really need to see in HD, and you don't have an HD TV set, then it really doesn't matter how much it costs: there are cheaper paperweights around.
Footnote: Microsoft is currently providing free access to TGS coverage and X06, its own event, via Xbox LIve. That will remain free until September 29.