Mark's sessions are one of the major reasons I come to TechEd. I always look forward to his sessions.
The time slice scheduler has been re-written to work better and properly report using features in newer processors. Vista can give multimedia applications higher priority than other applications to make sure the sound and video are glitch free. I think I have seen this myself while playing podcasts through iTunes while playing highly demanding games. Protected processes were put in to allow for secure memory for DRM or encrypted media content.
Symbolic links are now in Vista, use mklink. You can cancel I/O such as net use to non-existent server. I/O prioritization allows for background applications such as virus scanning, without changing CPU priority. Bandwidth reservation for streaming I/O to ensure media plays properly, also optimizes size of I/O.
Superfetch uses all available memory in attempt to predict what you will want to do and speed it up. It even watches what you do at certain times of day to try and prepare the machine for next action. ReadyBoost, ReadyBoot, ReadyDrive are all ready to help you.
Dekayed auto start upon boot for services so that the logon process is more friendly for users. Things like Windows Update can do this, hopefully anti-virus will do it as well. More reliable sleep transitions. Vista doesn't ask to sleep it tells the apps and drivers to sleep.
Volume Shadow Copy in Vista. Enables rollback on the client just like Windows 2003 server did for server drives.
UAC in 10 minutes in this session, 75 minutes in the session I am going to tomorrow.
4 integrity levels
Low - Protected IE
Normal - LUA User
High - Elevated user
System - System process
Virtualized files might have a hidden (to me at least) gotcha. If you have an application that has virtualized files and then is upgraded to have a Vista capable manifest it won't have access to those previously virtualized files. This could catch a bunch of people of guard I think with application upgrades.