I've had numerous conversations with customers about the frustrations of lack of synchronization of products coming out of Microsoft.  For instance, the fact that you can't use VS 2010 to do BizTalk 2006 development.  I continue to advocate inside the company for us to be better about this.  I won't bore you now with a list of examples of progress that we've made but we have made some and we are working on more.  In the meantime, with the coming BizTalk 2010 and the currently available Beta, you can now do BizTalk development with VS 2010.  Here's the Beta in case you are interested:

http://www.microsoft.com/downloads/details.aspx?FamilyID=0f852e77-f792-4784-b2d4-95113d40db64&displayLang=en

Brian