Personally, I don't care about the people who want to play their HDDVDs on their existing DVD players in their mini-vans. Backwards compatibility takes a back seat to technical excellence for me, and I don't want my standards watered down because of cheapskates who don't want to upgrade their crappy systems. I paid a premium for my home theater and I want hollywood to cater to my hi-def system.
People who once owned vast casette, 8-track, LP, laserdisc, beta, and VHS had to move on when CD and DVD came out, and those with crappy SD players and TVs will simply have to buy 2 copies, or rip their HD version and burn it on an SD disc.
This backwards compatibility policy is so retarded and shortsighted. In two to three years, HDDVD players from China will sell for $30-50, the price of 1 or 2 DVDs. And regular DVDs will go in the bargin bin $5-9.99. HDDVD should be the standard for the next 10 years, so don't compromise its introduction by layering on unneccessary backwards compatibility. It's like broadcast HDTV. I am not interested in the least of having a single TV signal which "downgrades" to NTSC for older sets like Color does on B&W. I'm interested in the broadcast technology which has the highest bandwidth, best efficiency, and best reception, even if that means older sets can't use it and everything must be broadcast twice.
I own over 800 DVDs now (about 300 bought from China). I will rebuy many of the classics when they come out on HDDVD. And I'll wait to buy HDDVD players for secondary rooms in the house later. If my kids can't watch the newest movie in their own bedroom, tough.
I don't even think it's good parenting anyway to let your kids have their own DVD player in the minivan or their room. Watch TV in the family room and supervise your kids. If they want to watch the newest and greatest HDDVD movie you bought, they'll have to come see it on the main set for a year or two until prices drop, whoop-de-do.
Being able to port a hi-def disc to auxilliary rooms is the least of consumes for HDTV early adopters (pretty much everyone now). I've got $20k sunk into my home theater. I'll pay $9 for a SD DVD copy or RIP and shrink it myself if I have to.
-DC
p.s. Since it was brought up, I think DVD players in the car are moronic, are brain pacifiers for lazy parents. As much as I love video and video games, I think its sad that people have to hook their kid up to a video screen 24/7. When I was a kid, some of the best times I had was socially interacting with my parents and others in the car, instead of fixating on a screen in front of me for the journey. And yes, I AM a parent, and yes, I have to deal with a screaming kid in the car. But the TV, DVD, and Video games, are too easy of a babysitter/pacifier. There are other things your kid can do in the car besides watch the boob-tube. (lets leave aside the stupidity of buying SUVs which are overpriced and unsafe, and paying a premium for internal DVD, but then complaining about buying a few SD discs or extra HD players)