What Are the Best Med-Chem Books?

I get regular requests to recommend books on various aspects of medicinal chemistry and drug development. And while I have a few things on my list, I’m sure that I’m missing many more. So I wanted to throw this out to the readership: what do you think are the best places to turn? This way I can be more sure of pointing people in the right directions.
I’m interested in hearing about things in several categories – best introductions and overviews of the field (for people just starting out), as well as the best one-stop references for specific aspects of drug discovery (PK, toxicology, formulations, prodrugs, animal models, patent issues, etc.)
Feel free to add your suggestions in the comments, or e-mail them to me. I’ll assemble the highest-recommended volumes into a master list and post that. Just in time for the holidays, y’know. . .