Choosing a UI technology is often very difficult. I've spoken to a great many developers who want to use one particular technology, but then second guess themselves. For example, they may want to build a client app, but have pressure from management to build a web or browser-based app, often with no clear technical reason. Or perhaps they want to update a Windows Forms app, and are wondering if they need to port it to WPF - and wondering how to do that.
In this interview (filmed at Tech Ed last year), Brian Noyes discusses all of this. He has some good rules of thumb and some advice grounded in his real world experience. Definitely a show to watch. On his blog, Brian summarizes some of his points. Worth a read also.