Ran across several tools today to help with performance monitoring. Of course, there is always the Visual Studio Profiler, but in addition there is:

• xperf from Microsoft, a part of the Windows Performance Tools (WPT) Kit
• WPF Performance Suite, also part of Windows Performance Tools Kit, including a visual profiler.
• MSDN also has a good set of documentation on performance guidance that can be found here: Optimizing WPF Application Performance