I'm one of those folks who've only read Hyperion This Year. It is probably the single biggest factor to my renewed interest in literary SF/F. But, I'm still within its afterglow, I'll exclude it.
I find Brainshades' list very interesting as three of his books--Anubis Gates, Locke Lamora, and First Law Trilogy--are on my immediate reading list.
But back to the question at hand. The first two are repeats. The third is not.
Rendezvous with Rama - Best thing about the original book--and not the climax of the sequel trilogy--is that we humans didn't know who built/sent Rama. It just is and we're left to ponder our place in the universe. I remember just being flabberghasted at the first book as my brain started expanding in my skull.
Ender's Game - It holds the distinction of being the only book that, upon finishing the last page, I turned the book over and started again. It was that good and I didn't see the ending coming. I don't usually like to predict what the author might do. I just want to go with the storyteller.
Star Wars novelization - Remember the summer of 1977 and seeing that movie for the first time? It was eye opening for an entire culture. As good as the movie was, I enjoyed the novel a bit more. You see, all the extra scenes were in ther, the ones Lucas edited out. But, than that, I got the sense that the events of Star Wars was smack in the middle of something larger. There was so much to know and learn. There wasn't any whiff of what we got ("No, Luke, I am your father."). What we got was a pure adventure story about a boy, a girl, and a galaxy. It was everything I ever wanted.
BTW, I reviewed the Star Wars novelization a few weeks ago at my crime fiction blog.