Getting prepped for our new Pathfinder campaign I find it remarkable how useful the Rules Cyclopedia and Swords & Wizardry core rules are to me. So much solid advice and useful tables - like the random dungeon stocking tables. I have yet to actually reference any of the Pathfinder books (not that they are bad, but like all later D&D they are just lacking in actual utility). I wish we were playing a different system . . . but we have to keep the players happy I suppose.