What's your favorite non D&D/d20 book to use in D&D??
I love Library of Bletherad from palladium book,a nice book filled whit a lot of info,col magic weapon and the strangest way of handeling justice i have evert seen.
Central Casting Heroes of [insert genre here]
I've used a lot of the monsters from Bruce Galloway's Fantasy Wargaming, and just converted them to D&D.