A recent feature poll on the MSBuild blog seems to indicate that a debugger for MSBuild projects is the #1 vNext request from you. Lot of other folks (such as here and here) have explicitly blogged about this requirement.
Over the last week I put together a Visual Debugger for MSBuild Projects. The v1 alpha feature list looks like:
I have also uploaded the binaries and how-to-get-started instructions on http://www.codeplex.com/msbdbg.
Please head over there to give this a spin. I have also listed there the known issues, the v2 plans, and other details there.
I am looking forward to listening to you on the right, wrong, the good, bad, the ugly and anything else that you will care to tell me about.
I am hoping this will go some distance it helping everyone get away from printf debugging and get into full fledged debugging for MSBuild projects. Esp. considering MSBuild projects files are no longer used only for builds. (Why, my wife has even filed a patent for using MSBuild as a test harness)
Here are a few screen shots: