I must admit this post is for me as much as the rest of the internet. One of the questions i recieve on a semi regular basis is "Do you have any productivity case studies for Visual Studio Team System?".
Unfortunately these queries don't come in frequently enough for me to memorize the URL and our search tools always seem to take longer than i want-g.
The best resource is the page Brian Keller put together highlighing the best of the best of these case studies:
Team System Customer Evidence
Brian also pulled together the entire list to make it easier on the search challenged like myself:
Oh yeah, Brian is always ont the look out for a new case study if you would like to add yours to this list!