I am going to talk about this as a complete series, since that was how I read it and it is written as one long story arch anyway, so no real need to split it up among TPB volumes.
Preacher is a series that was done by Vertigo back in the 90s and, in my opinion, is everything awesome about the 90s in comic book form. You have some ultra-violence, some antihero action, some morally ambiguous characters that you love, but shouldn’t. a little rock and roll, drug abuse, boobs, and probably the best part, just a little fun irreverence (as in, the whole plot of the story).
So the story follows this guy, Jesse Custer, who starts out as a preacher who kind of hates the job and hates the people he shepherds. He likes to drink and smoke and generally have a good time. Well, during a sermon, he gets hit with this crazy power. Everyone in the church dies, but he walks away. Apparently when demons and angels do the nasty, their spawn is a being with basically the same powers as God. When that spawn, known as Genesis, possesses a person that person gains the ability to make people do whatever he says. Pretty friggin sweet! That is what happens to Jesse Custer, The Preacher.
Once endowed with/possessed by Genesis, Jesse goes on a journey to find God, not in like a metaphysical sense, in the God-abandoned-heaven-and-is-hiding-on-earth sense. God gave up on humanity and heaven and all that, and decided to take a little vacation. Jesse aims to find him and set him straight.
Jesse and his friends, long lost love Tulip, and hard partying vampire Cassidy, journey all over the world, fighting mutant rednecks, a whole religious/political secret underground, an undead cowboy assassin, various angels, and, oh yeah, don’t forget arseface!
The story is ridiculously absurd, but super fun and easy to read. There is a ton of humor. Great storytelling. All around great series that is well worth the read. If you are new to the comic world, or are looking for a good story to try out, I would definitely give this a shot, assuming you are not easily offended.