The team at Vertigo that created the nice Family.Show WPF sample wrote up a summary of their key feedback and take-aways from the project, and they're well worth a read. One tip in particular that I liked was regarding data binding, and default values. They advised setting the default values in bindings to give a better design-time experience in tools like Blend, which uses the defaults when it displays the UI in the designer. The source-code is also quite tractable, consisting of about a dozen xaml files and ~20 classes.
