I remember reading Piers Anthony's Novelization of Total Recall in Middle School, before I knew that the movie was an adaptation in the first place from a Dick novel, and thinking that the novelization was a lot more coherent and interesting than the movie was.
Slate has an article about what's happening to movie novelizations.
I've always been sort of intrigued by the concept of the novelization. A "novelization" is an novel adaptated from a movie, so there's no reason it couldn't be as interesting as a movie adapted from a novel. However, because of economics that hasn't often been the case; it's so much cheaper to have someone write a novel than make a movie that novelizations are often simply part of the marketing budget for a movie. Slate makes the case that because novelizations were originally so people could relive the movie back before the days of rentals, and because DVD's are making people so accustomed to bonus materials, that novelizations are increasingly divergent from the original film, and further, making greater efforts to expand upon them. Which is making the novelization more interesting.
I'm open to suggestions as to novelizations that would be so much as worth recommending on this site.