I've Been Meaning to Mention This One for Ages,
But Like a Moon-Calf, I Keep Forgetting

I am the proud co-possessor (with the Significant Other) of a complete second edition Oxford English Dictionary, but of course one wants to have a nice one-volume thing you can use to look up words casually. Well, a while back I acquired Samuel Johnson's Dictionary, which I suppose I shouldn't really trust all that much, but it's so damn fun I can't resist. And certainly comes in handy when I'm looking at historical novels; in The Confusion Neal Stephenson makes a reference to a "Nine-Hammers" that I couldn't quite figure out, until Johnson pointed the way to the "ninnyhammer," otherwise known as a simpleton.