I've been reading comic books on and off since I was 15. Out of all of the books I've read, Irish writer Garth Ennis' Preacher has always been at the top. It's violent and offensive and completely subversive. On top of all that, it's a classic in modern storytelling.
But Garth Ennis is much more than Preacher. He's been an active and prolific creator for over 20 years, staying away from the mainstream with his decidedly adult works until his recent work on Marvel Comics' The Punisher, upon which both recent movies were based.