Here's an in depth look at how we built Visual Studio 2008 as told by one of our principal architects responsible for developer productivity. As you might imagine, trying to get a very large team like ours to successfully ship a high quality product on time is a monumental effort. Good news is that we use Team System to help us make that happen. Read more about it here: http://howsoftwareisbuilt.com/2008/03/04/interview-with-mark-osborne-developer-division-architect-microsoft/.