Kinds of Mistake(s)

At today's workshop I said that one should always write "kinds of thing" not "kinds of things". I wasn't sure that it was a rule, and I promised to look it up. Well, it would seem that I was wrong. The Chicago Manual of Style's online Q&A page says, "According to Webster’s, 'kinds of' takes a plural if the relevant noun is countable."

I'm still not sure, however. Most of the online discussions about this seem to favour "kinds of cat" and "sorts of cat" over "kinds of cats" and "sorts of cats". Certainly, I would always write "varieties of cat" not "varieties of cats". There is something, well, crisper about the singular after "kinds of", "sorts of" and "types of".

Most online usage, however, does favour the plural where possible. (Don't ever write "kinds of funs", for example; always write "kinds of fun".) Well, there are many kinds of grammatical error. In my own writing (as you just saw) I'm going to stick to my guns (I have several kinds of gun, of course). But I will also stay on the lookout for a better argument for my usage.