http://www.microsoft.com/events/executives/billgates.mspx
You can watch the presentation here.
It was a fairly good presentation compared to usual (in my opinion).
They mostly went over Windows Vista (which looked pretty good) and MS Media Center (looks to greatly improve).
There was a presentation of HDDVD with The Bourne Supremacy (or maybe it was Identity can't remember now) using the Toshiba HDDVD player which is supposed to be available soon for $499.
BluRay seems to have won the next-gen DVD "war" in recent months, but I gotta say HDDVD seems pretty cool and if it's true the initial BluRay players will be $1000.00+ with HDDVD coming in at $499 a player, this might not be over yet.
Some of the cool features they showed were being able to bring up menu features/special features etc in-movie in a transparent menu bar at the bottom of the screen. An example shown during Bourne Supremacy/Identity/Whatever you can bring up a menu strip showing recent actors appearing in the movie and finding out their history etc. For when you're watching a movie and going "where do I know that actor from?!?!". Pretty nice feature actually.
Another demonstration with HDDVD was "Legal Copies" to your PC. I think this could be a big selling point for HDDVD if it's true BluRay is going to be super hardcore about copy protection. You can legally store your HDDVD's to your PC (Media Center PC only though? not sure) and you can make backups specific to how you want to reuse it. Like a portable device backup, full HD backup etc.
The last interesting thing in the MS keynote is they're going to be releasing an external HDDVD player for the Xbox 360. They didn't go into specifics but I'm personally imagining something akin to an external PC DVD-R ROM type thing connecting to the Xbox 360 via the USB plugs on the front of the console. No word on pricing and they didn't show any actual unit. I'm assuming the Xbox 360 would process the video/sound through the console.
Anyway, just a heads up for anyone who's interested in all this new tech.