I'd have to recommend Lustmord (
http://youtu.be/V3g5bSm8c7k) for music, he's just so bleak, and hits something instinctual in me. Right in the back of the insect brain. There's a degree of supernatural implied in the music, but I think it sets the right kind of tone for an AW game.
Also, Google for
Nigeria Hyena Men. Something worth a playbook, I think. Unless there's already an advancement move that turns an existing playbook into
Guy With A Scary Fucking Pet That Will Rip Off Your Face. In fact, seems like animal handlers would work well in AW.
Don't know that it's been mentioned yet, but Jack Vance's
Dying Earth novels, and the subsequent
Songs of the Dying Earth strike me as a great source of character for AW, and definitely sets the tone for how people treat one another at the end of time. Certainly not a direct inspiration due to its being essentially sword and sorcery (besides, Robin D. Laws already did it so well), but the interpersonal relationships on Old Earth just sing Apocalypse World to me. Seriously fucked up people doing batshit crazy and sometimes truly horrific things in order to get what's coming to them.
Have to second
The Road, especially McCarthy's world building. The Man and The Boy don't entirely fit into playbooks, but just about everyone they encounter does-- up to and including the Old Man hocus-without-a-cult.
Since zombies/un-zombs have already been broached, can't recommend
The Walking Dead enough. Both the comic and the series are must-sees. Not only are they great fodder for the near-apocalypse past of AW, but the long-form decline Robert Kirkman intends for the books (and one would assume, what Frank Darabont plans for the series) is absolutely the Apocalypse World, walkers nonwithstanding.
Ed Brubaker's
Criminal comics and Richard Stark/Donald E. Westlake's
Parker novels are great sources for what desperate people do to one another, and the social dynamics that grow out of a fundamental lack of control.