I always had a couple of the Creepy/Eerie issues floating around in my stuff. The Ditko work in them looks gorgeous, and everyone always raves about them (fans and pros, alike). Well, I discovered that most of the stories for Warren were reprinted in Eerie #135, making it a veritable GEM for a seeker like myself.
Not sure how long this link will last, as its an Ebay image. The book is quite affordable, and gets you the bulk of Ditko's Warren work.
There've been a few scans posted here, so if you haven't seen them, take a peek. When I get a better grasp on the work as a whole, maybe I'll post more info.
DADDIO