WPF Inspector is an awesome open source utility to troubleshoot common problems with WPF applications. It was created by Christian Moser and can be downloaded from Codeplex. This is a short introductory video that I made for it.
Developer Tools Screencast 1 : WPFInspector
P.S If you are interested in tools that make you more productive, and work with Sql Server Management Studio, you should check out SqlSmash.