Microsoft released a pair of "fix packs" for Windows Vista, which are targeted to improve performance and compatibility.
Among the reported fixes are improvements for speeding up Vista's hibernate and resume performance, improved compatibility with printers, tweaking Vista's memory management capabilities, better HD DVD/Blu-ray playback, and improvements in file transfers.
Perhaps the most noticeable fix for gamers is an update that cures an issue with graphics cards using Nvidia's G80 (8800) GPU. When firing up a game, the 8800 takes a little time to ramp up?'too much time for Vista, which thought the card was hanging. So the game would quit, and you'd typically see the "Windows has recovered from a serious error" message, which would point to the Nvidia-based card.
Also fixed are performance issues with high definition disc playback (both Blu-ray and HD-DVD), file copy performance improvement and improvements to compatibility with Canon cameras and HP printers.
Both updates are currently downloadable from the Microsoft knowledge base. Fix KB938194 is about 2MB, while update KB938979 is about a 10MB download. The patch files are available for both 64-bit and 32-bit Vista.
You will have to go through a more-annoying-than-usual Windows validation process if you want to download the files, but if you wait about a week, both fixes will be available through the normal Windows update process.