Microsoft has released an updated to Vista RC1, build 5278, as described on the Vista Team Blog. I downloaded this over night, but it does not install into a VMware VM. I'll have to cut a DVD and try it on my Vista PC. My new laptop has not arrived yet, so I'm not able to run this to see what improvements have been made.
This release is being made to the general public, and you can get the new build in the following languages: