VS: Modules Window
I've worked in various version of Visual Studio just about every day for the past 4 years. Today I learned a new feature: the Modules debug window.
I'm trying to create test the debugging scenario when a specific set of symbols is not loaded. But no matter what I tried, it was still finding the symbols somewhere on my machine. A quick trip to a teammate down the hall taught me to use the Modules window. This not only shows which symbols are loaded, but it also gives the absolute path to the assemblies.
MSDN has a full description of the Modules window and the information it contains.