Preacher

Preacher is a series by Garth Ennis and Steve Dillon. Published by Vertigo, it ran for 66 issues. There were also a few one-shots and a miniseries focusing on secondary characters.
The story revolves around Jesse Custer, a reverend from a small Texas town who one day finds himself merged with a divine entity known as Genesis. Along the way he learns that God has abdicated his throne and sets out to find him and make him pay for all the injustice and evil He's allowed to happen. Custer is accompanied in this quest by his ex-girlfriend, Tulip, and a 100-year old Irish vampire named Cassidy.
They are primarily antagonized by two forces: one is a secret society known as The Grail, who are esentially running the world and have a particular interest in Jesse's newfound abilities. The other is The Saint of Killers, an unearthly assassin tasked with the goal of killing Genesis.
The main series and peripheral titles have been collected in nine trades, and should be read in such order:
1	Gone to Texas 	Preacher #1–7
2	Until the End of the World	Preacher #8–17
3	Proud Americans 	Preacher #18-26
4	Ancient History 	The Saint of Killers #1-4, The Story of You-Know-Who, and The Good Old Boys
5	Dixie Fried 	Preacher #27-33 and Cassidy - Blood and Whiskey
6	War in the Sun 	Preacher #34-40 and One Man's War
7	Salvation 	Preacher #41-50
8	All Hell's A-Coming 	Preacher #51-58 and Tall in the Saddle
9	Alamo 	Preacher #59-66