Fair enough, I suppose neither is really an adaptation so much as they are both a collaborative effort. Still, they are different and both work well, in my mind they are a more true pairing than a lot of things.
I will throw A Clockwork Orange onto the list as well. The movie and book have totally different messages and themes, but state them equally well and manage to do so with strikingly similar material. They are so much alike and yet so different that it’s somewhat astounding.
This is why I stay on the Dope. Wasn’t it just a feel good movie? The book is very funny–lots more “misunderstandings” and misconstrued phrases etc. I read it in one sitting–couldn’t put it down!