I've got everything "working" on my system. I'm using XBOX HD DVD player, Windows XP w/ Athlon X2 4200+ (not too impressed with that), GeForce 7900 GT VGA output to Westinghouse 42" 1080P LCD and Cyberlink PowerDVD 6.5 for HD DVD.
I was not able to use the DVI output, Cyberlink gave some kind of licensing error. I've only tested it using the King Kong DVD that came with the XBOX HD DVD. All the hints mentioned here on using PowerDVD were necessary. It defaults to captions on and that stupid PIP. (Why would anyone want PIP of the same movie during a movie?) I also had problems with the movie displaying after the FBI warning etc. The sound would come on, but no motion picture. Changing the scene or time shifting manually would cause the movie to start playing correctly. I also have found that pausing the movie can cause the sound to go away permantly requiring a complete restart of PowerDVD to get it going again.
That said the picture and sound quality is great, an obvious improvement over DVD. It would be nice to have some screen scaling to that I could fill my 16:9 screen instead of having the black borders. I can't wait until Media Player Classic has HD support. I also tried changing the advanced HD DVD setting in PowerDVD to use widescreen instead of HD format just to see what happened, and no picture would display.
Well, I'll be renting some more HD DVD from Netflix and the near by Blockbuster says they are getting in HD DVD titles next week (they already have BalloonRay). I've been watching broadcast HDTV for over a year now, so I'm pretty spoiled and ready to see all my movies in HD, though I'm not really ready to spend a lot of money on it.