Interestingly, one of the series I have reread over the years is The Chronicles of Narnia, not even realizing that I would thus fall within Lewis' definition of a good reader of literature.
There are few other works of fiction I reread unless I am going to teach them, because it is so true that knowing the ending detracts from the experience. However, if I do lose it someday, just think of how much I'll enjoy again the books I already own!
I have also noticed that some books read in my youth are disappointing now. I do think this is a function of a better reading sensibility, but I also think that some books are of their time and moment, and if one is not living in that time and moment, the book lacks something.
I do reread nonfiction from time to time, since knowing the end of the story in no way interferes with the journey. Often, with history, sociology, or psychology, for example, the book is enriched because I know more and am able to make better connections.