One of the coolest things I got to find out today from the PM of the MSBuild product, Kieran Mockford, is that development on the next version of MSBuild has been done using Test Driven Development. Yep, Write a test that fails, make it work, refactor. In fact, since it started long before Team System, they used NUnit to develop the unit tests.
Kieren informed me that he considers to be a great help to the product and he's very happy with this method of working. He's a great guy and very interesting to talk to.
This just goes to show you that this "hype" is not just buzz words flying around. Its being done by real people on real projects, even at the largest scale, and it proves itself every day.
As for MSBuild, One of the main concerns I had was whether we're going to get a good configuration tool to go with it. The current answer seems to be "no", but from non-official discussion it looks as if such a thing is being considered one way or the other.
As Kieran will be doing a talk tomorrow about Team System, I'll try to get him to do a small interview with me about TDD and MSBuild. We'll see.