I just recently started using my own build of Castle.*, built with PDBs and not strong named, so I can step into the source code and understand better how it works.
I find it interesting that before I had PDBs, I could Go To Definition at design time and see the public interface of any Castle.* (or any other really) type - one of my favorite new features in VS2005.
However, now that I have PDBs, I sometimes start debugging as a short cut to go see the source code - the PDBs know where the source code is, but G To Definition doesn't.