Probably Dahl's best book was Boy, which isn't a kid's book. The title comes from his mother's way of addressing him. She called him, simply, "Boy."
Also, remember, James and the Giant Peach was directed by Tim Burton, a very dark director.
"Charlie and the Chocolate Factory" I believe is the correct name of the story. I liked that as a kid, also "Charlie and the Great Glass Elevator", though I don't remember it much. My fave was "James and the Giant Peach". I once saw a water tower in South Carolina and it reminded me of that story.