I usually buy all "big three" guidebooks for the places I go (Lonely Planet, Rough, Fodors). It looks as Fodors is geting better and better, and keeps the fresh unbiased look, while the others are stuck with their image. Especially for Spain, Fodors is almost ideal. Descriptions, everyday facts, maps, historical hints, close up looks, "break" recommendations during a museum visit etc. I am an architect, and I think that it is the only guide that offers info about architecture and art, without being overtouristic or overacademic. The best choise if you travel to Spain, and propably to many other places as well.