I'm doing a Silverlight app as well (project management/code editor tool--does it sound like a solved problem? Why, yes, it is!). I concur with much that has

I'm doing a Silverlight app as well (project management/code editor tool--does it sound like a solved problem? Why, yes, it is!). I concur with much that has been written, but here's a few other comments... If you are working with RIA/WCF Services and the Entity Framework, if your app isn't straight up CRUD, data access gets a bit kludgey really quickly. The asynchronous calls from the client don't help. I also agree with another comment that points out that there is little that Silverlight can do that a good JS-driven UI can't. We grudgingly moved to Silverlight because it allowed some degree of interoperability with our main product (which runs on PDAs and tablet PCs--data collection devices)--the web app will allow users to build UI flows for the devices, and thus we can use the controls already defined for the devices in the Silverlight app. I suppose that's one on of the selling points of XAML, but I haven't done enough work on the UI to make an informed decision about it.