With that said, I have to make it clear how great these books are. They're excellent guides to haunted places all over the state. Especially cool are the little "Fright Bites" sections at the end of volumes III, IV, and V. As you may have noticed, I was tipped off about a lot of my hauntings by Chris Woodyard's books--although honestly, at this point I've gotten many more from other sources. She did help me get it started, though, and has e-mailed me about the site. You can see her own book sales website at invink.com.
There's a lot of material on the Dayton area in the Haunted Ohio books; it's where Chris Woodyard lives. She pegs Waynesville as the most haunted town in the state. I'd have to go with Athens, but that's just me. Read the books and make up your own mind. For sheer volume of material, you just can't beat them.