For Joy of Cooking: I haven't read the most recent incarnation, but the last time they completely revised it, they ruined it for me. Perhaps I just got used to the quaint tone of the original, how everything seemed geared toward southern formal dinner parties, but Ethan Becker's first rewrite just didn't work for me at all. I have used literally hundreds of the cooking recipes, and hundreds of the baking recipes as well. The cookie and bars section alone is worth the price.
This one is the orignial and best