Just as it says, after installing the Windows SDK for .NET 3.5, intellisense in VS 2008 stops working.

I followed the steps for the manual re-reg of TextMgrP.dll and things seem to work ok.

Microsoft Windows SDK Blog : Workaround: Installing Win SDK after VS2008 breaks XAML Intellisense

There is some chatter these days about the WPF (and other .NET 3.5 techs) test for MCTS - I guess so far in beta. Here's the info on the WPF test.

Preparation Guide for Exam 70-502: TS: Microsoft .NET Framework 3.5 - Windows Presentation Foundation