Silverlight Spy - Visual Debugging Silverlight Applications

Koen Zwikstra has created a very useful tool for Silverlight application development called SilverlightSpy.  Load the tool, point it to a web page with a Silverlight application and the dissection begins.  It has a little bit funcitonality from of all of your favorite tools like Snoop, Fiddler, FireBug and Reflector but made specifically for Silverlight.