Because I am inspired by non-children's art too, I added:"Rolling Stone: The Illustrated Portrait" by Fred Woodward
There are many others that I find inspiration from and look at over and over, but if I were asked again in a year or two, I bet these would still be top on my list.
The AD that was at the workshop commented on how surprisingly different some people's inspiration pieces were from their own style. How about you? What art inspires you?