Let the hive mind of Engadget get that for you.
"I need help! I want a small pocket camcorder but I'm not sure which one to get. I don't want to fall into the hype of the Flip because I worry two hours won't be enough. What should I be looking for when considering a small camcorder and where can I get a good quality one with expandable memory? Thanks!"
The update also improves the HD audio quality (i.e. HD formats such as Dolby HD can now be downmixed to DTS 1.5Mb, not just Dolby Digital 640 Kb as previous).
Obviously the best option is to pass through uncompressed Dolby HD directly but XBOX does not support HDMI 1.3 - so the new DTS 1.5Mb output option is still a decent improvement (or you can now select the uncompressed PCM option - if you don't mind stereo).
Oh, for those who need to find this option - when playing a HD DVD, select display and choose audio option which will bring up new menu.