Vista RC1 and Quicktime, java don't work. I found this out yesterday after installing RC1 and then installing quicktime. The aero glass effect got disabled. I thought it was something to do with my graphics card but just as I closed quicktime everything was ok.
Then while searching for this found these links-
http://www.microsoft-watch.com/article2/0,2180,2022483,00.asp
http://www.javalobby.org/java/forums/t78880.html?start=0

There is already some talk going on about this being one of the tries to kill java on the long term which I think is very foolish.