I've always loved the work of Hogarth since a "Dryden, Swift, and Pope" class I took as an undergraduate in which the professor used Hogarth's images to illuminate the texts, especially the earthier ones of Jonathan Swift. When my wife and I traveled to London a few years ago, I got to see some Hogarths up close in the National Gallery, hung in sequence as they were originally meant to be seen.
Art Spiegelman has always struck me as an underrated artist. To me, he is the Goya of our age, documenting not only the 20th century horrors of the Holocaust in Maus (pictured above), but also the 21st century tragedy and aftermath of 9/11 in In the Shadow of No Towers. Artists such as Spiegelman are the true superheroes of our age in their ability to turn tragedy into art and to use even cartoonish pictures of mice and cats to make us look more closely at our past, our present, and our future.