Rules to Better WPF and Silverlight

• Do you follow Composite Application Guidance (formerly code-named "Prism") in your Silverlight (and WPF) Projects?
• Do you use dynamic application loading in Silverlight?
• Do you avoid using Thread.Sleep in your Silverlight application?
• Do you offer out-of-browser support?
• Do you use the MVVM pattern in your Silverlight and WPF Projects?
• When do you use Silverlight?