If you like Preacher in terms of screw up situations, then you must like The Boys

http://en.wikipedia.org/wiki/The_Boys_(comics)

Here's some of the rare one I like :

Blankets

http://en.wikipedia.org/wiki/Blankets_(comics)

Real life biography, tell about his childhood, love and conflict between self and his own religion.

Epileptic

http://en.wikipedia.org/wiki/Epileptic_(comics)

Real tale about how the author cope with his older brother's epileptic.

Other Batman stuff beside Frank Miller's ground breaking graphic novel.

Batman : Arkham Asylum (FYI, this is way before Warners game came out)

A Long Halloween

Batman : Killing Joke (with all respect to the late Heth Ledger, he got nothing this one)

Batman : Year One

Some DC Comic stuff I enjoy :

Kingdom Come (seriously, read it, Alex Ross' art is just classic and amazing)

As for Japan manga :

Pushman

Goodbye

All by Yoshihiro Tatsumi. These are not your typical chibified, moe-fied manga. he mangas pictured harsh reality of modernise Japan in the post-WW2 era.