Lutz Roeder's Reflector is by far the most useful development tool I have, besides Visual Studio of course. Often times it gives me what I need to know faster and more accurately than MSDN. So much love goes out to Lutz for such a great contribution. There are several super cool things in the new version.
Scott Hanselman has a nice post explaining some of the new features in greater detail than I care to if you like. Or you can just go get it already:
- Reflector 5.0
- Reflector 5.0 Add-Ins via CodePlex