Re: Great Books for Fantasy and Sci-Fi Artists
For inspiration: Anything by Brian Froud. He has a great knack for drawing and painting fantasy that is not cute and cuddly.
Also Coffin:The Art of Vampire Hunter D. Not cheap, but a very different take on fantasy. Yoshi()taka Amano has a very distinctive style. You can get a taste from the VHD covers and illustrations. He also has an illustrated Version of the Magic Flute out.
I agree with the plugs for Impact.
The various "Eyewitness" children's books have great photo references on all sorts of subjects. Available in lots of libraries. In fact I find photo books, trave guides, and natural history field guides to be great sources. Lots of strange looking creatures, interesting architectural details, clothing etc scattered about the real world. I did a nice drawing of a lizard-man compositing a Maori warrior and a marine iguana. Very different to the traditional swamp dweller.