While l haven't done one of these in a while, I've also read some great articles recently, so here goes

• Mvvm THE MODEL-VIEW-VIEWMODEL (MVVM) DESIGN PATTERN FOR WPF  Josh Smith
• MEF Managed Extensibility Framework – Home  Glenn Block
• Composite WPF Prism: Patterns For Building Composite Applications With WPF  Glenn Block

Guess what I'm working on :-)