For those considering Silverlight, the Microsoft Patterns and Practices Team has a set of recommendations with sample code.  Originally released in C#, Version 2.0 is adding sample support (the guidance is essentially the same for both languages) for Visual Basic.  A copy of the updated guidance with VB specific examples is available at:

Visual Basic QuickStarts and How-to Topics for the Composite Application Guidance for WPF and Silverlight

Download a copy - I am.