I don't think we could possibly talk about monsters without mentioning the late, great Frank Frazetta. Though I've never been a huge comic kid myself, Frazetta's work wows people from every walk of life--and I am certainly no exception. Though he's probably best known for his musclemen (Tarzan, Conan), Mr. Frazetta was a prolific artist through the 50s, 60s, and 70s, creating a great number of magazine and comic covers. Check out these monster covers he did for Creepy Magazine (I know, right...it was a comic compilation) from 1966 and 1967!
Well-played, Frazetta. Well-played. For more Frazetta glory, see this American Art Archives gallery or his strange posthumous website!