There isn't an very much in Vista which compels me to go out and buy it. ReadyBoost looks very cool but they dropped two of the the features I was closely watching, WinFS and the new shell (MSH or Monad).
Most of what was upgraded in Vista is shiny stuff I'll turn off by default. I'm using XP at the moment, but It looks just like Windows 2000 / 98 because that's what gives me the most screen real-estate for the content I actually want to view. The ribbon UI in Office is another example of how Microsoft were busy wasting screen real-estate when they should have been creating a resolution independent UI.
Overall I feel that people are finally seeing Microsoft for what they are, a bunch of pigeonholers.