For one thing, I didn't know that Denny is Denny! Damn, that's cool! Big props. Going to order Experimental Brewing to celebrate.
I really like Designing Great Beers and feel like it digs deep in a couple of ways most books don't. I just ordered Brew Like a Monk. Like you, I've read most of the beginner books, and I'm trying to get into the next tier.
Looking forward to more suggestions.