Battle Pope is a fun apocalyptic romp featuring the Pope, who's a cigar-chomping, whore-banging midget which God imbues with totally bitchin' guns and muscles. Also, Jesus is his sidekick.
Y: The Last Man may be the best non-superhero comic book you'll ever read. It's a nearly finished 60-issue limited series, and the trade paperbacks will catch you up in time for the epic conclusion.
I'm not sure if Marvel Zombies counts as a superhero book, and I haven't read it, but I only here great things about it. Basically, all the Marvel superheroes have been turned into flesh-eating zombies, yet still retain sentience. The latest series pits them against Ash from Army of Darkness.