I stumbled across a beautiful book in my finance, Meghann's collection (now mine as we'll ;) "Edgar rice Burroughs, Tarzan and the City of Gold" illustrated by Tony Sgroi. I was first impressed by the quality of the illustrations and then I saw the duo-tone, pink and green and thought, how beautiful this simplicity is. Solid, bold line work paired with a flat, solid color gets me every time.
Fantastic design.