Building any project based on what is currently the flavour of the month in Redmond is the quickest way to go insane. Having been through the full gamut of Microsoft technology upgrades from MFC, via ATL, to Web Forms, Silverlight and ASP.NET MVC. The lesson I learned is pick the tool that best suits the job in hand and for which your development team have the skillset for. As long as you can build the end product that makes your customer happy, then you've chosen the right tool for the job.
Read the Joel on Software article 'Fire and Motion' for more.