One of the coolest new features to be part of VSTS 2010 is the Historical Debugger. It hasn’t gotten a lot of buzz, so you may want to check out this 10-4 video.
If you aren’t familiar at all with the Historical Debugger, I stole this blurb from the video web site…
The new Historical Debugger coming in Visual Studio Team System 2010 promises to revolutionize the way you debug managed applications. You can think of it as something of a VCR for your debugger; "rewind" the debugging trace to examine the state of your application at various points in time so you can all-but-eliminate the guesswork about where to place your breakpoints prior to pressing F5.