Many have “heard” that you can now step into .NET source code when debugging in Visual Studio 2008. For those who have not been doing this since the start of the year, you can find excellent instructions for configuring Visual Studio to get the necessary symbols here.
I highly recommend understanding this process and making it a part of your debugging routine. It often becomes necessary to understand why the .NET framework is behaving in a certain fashion while developing. By stepping into the source code and using the watch window, I’ve saved myself a lot of hours of head-scratching. More often than not it’s as simple as understanding why an exception was thrown and the hidden meaning behind the message. Within minutes I can usually pinpoint how I was incorrectly using one of the libraries, fix the bug, and be on my way.