Best Craft Book Ever" is so great, I agree with it's title, for sure.
Kathy Ross books are old school, and I think out of print, but they are so great. (find them on eBay or amazon)
Rosie O'Donnell one as part of a giveaway on Mod Podge Rocks, and it's also really got some fun projects in it.
toddler art books I found really resourceful when I used to do children's ministry - toddlers are so unpredictable, their art projects are different than bigger kids and these had some projects in them that were very resourceful and clever.