Not to horn in on Parabasis territory, but having never been a comic/graphic novel person in my youth, and now having a sister who is amongst other things a comic writer and illustrator, I decided that it was time for me to start giving myself a rudimentary education.
I started with the Alan Moore/Brian Bolland collaboration Batman: The Killing Joke. The image of the Joker as presented is interesting, although the flashbacks to Joker's past don't quite add up to what I was hoping it would get into -- the philosophical sketch that Alan Moore places at the center, that a madman is only separated from a normal man by "one bad day" is interesting but not the meatiest.
What struck me, however, is really Brian Bolland's treatment of the Joker's face. The Carrot-Top-like young comedian, and the manic, brutal face of the murderer-rapist Joker are fantastic opposites -- but the moments where they blur between the two are just visually interesting. Seeing as The Killing Joke really is, more than anything, a portrait, I feel like Bolland really delivered the visual equivalent of that.