We have started publishing case studies for the upcoming release of the .NET Framework 3.0. This will be added to as we move through the release and launch activities.

http://msdn2.microsoft.com/en-us/netframework/aa497320.aspx

You may have noticed also that the WinFX developer center on MSDN has finally gone away. This name was changed / merged with .NET Framework back in June so you can now find out about those same technologies at http://msdn.microsoft.com/NETFramework. Those technologies of course being Windows Presentation Foundation, Windows Workflow Foundation, Windows Communication Foundation and Windows CardSpace.