Project references are problematic
I found another problem with project references. Somewhy project refer to DLL files in sdk directory and that makes debugging pretty annoying task. I think you should use references to projects because this way it is easier to debug applications in solution. I also suggest to use local references to projects DLL files and not to use GAC - it caused me problems because VS was not able to read correct versions of DLL-s and wasn't therefore able to show any debug information normally.