I was in a meeting yesterday where I and a person from Microsoft were presenting on Team System to one of our clients. During the presentation I found out a nice piece of information about companies who already have MSDN Universal subscriptions. Microsoft is automatically upgrading each of your Universal subscriptions to one of the versions of Team System (Architect, Tester or Developer). I also understand that you can upgrade to Team Suite for around $1000. It is also cheaper to go ahead and get an additional Universal subscription for new users (like testers) and then have that upgraded to one of the versions.
That being said, it is my humble opinion that web tests are one of the best new features of Team System. Web tests are not included in the Architect and Developer editions and as such if I have to choose between dynamic and static code analysis and web tests, I would rather have the web tests. This means that I would purchase the Tester edition of Visual Studio Team System for them and then one or two Architect or Team Suite Editions.
Happy Coding!