William Safire has always thoroughly pissed me off. I see him as a sort of learned dolt. He's stuffed a lot of beans in his noggin, but doesn't know how to take advantage of it for anything but clumsy invective.
So it's fun to watch Language Log take Safire to task for his expressive prescriptivism in the matter of "which" versus "that". Language Log has been one my favorite sites ever since I learned that the entertaining Geoff Nunberg from NPR's Fresh Air pitched into a blog (I also appreciate that Nunberg is on the usage panel of the best American dictionary: the American Heritage).