As detailed here, we've released an update to XNA Game Studio Express today. You can get an idea of what's in it by reading this announcement post. The primary goal of this release was to get official Vista support into the product. We also took the opportunity to fix a bunch of bugs and add a few new features. Many of the bugs we've fixed and features we added came directly from you, so I hope you enjoy this release and thanks!
Now on to the next release!