With a whole new workflow runtime based on the pretty rock solid WCF implementation, this is one little monster of a release. Visual studio is getting quite a nice facelift and the framework with ton of cool features like side by side execution and lots more.
The new flowcharts and the WF designers, with the mini map and argument and variable docks, should be quite an interesting experience. I am really excited to see an increase in the WF usage for applications with its boost in performance and improved usability.
You can find a lot more screen shots here
MSDN subscribers can download here.
For the rest of the world it will be available tomorrow.