This post at SF Signal shows which books supposedly are for the "dumb" kids, and which ones are for the smarties, as evidenced by the correlation between favorite books and SAT scores.
I highly recommend you read the original article, but here's the graph they include, for quick reference:
Hmm, interesting. I'm quite surprised to see that the average score (on the older 1600-point scale, rather than the new 2400-point one) does not go any higher than 1250. At any rate, I know loads of people who scored way higher than this entire range, and who loved many of the books on the lower end of the scale.
My favorite book is Ender's Game, but I'm also quite partial to Harry Potter and the Chronicles of Narnia (just to pick examples from this list). My score was about 1425 (790 in English, thank you very much). My wife is not nearly as partial to Ender's Game, but liked Eragon and loved Wicked and Harry Potter (though her favorite books, most by Connie Willis, aren't even on this list). She scored a 1590. I knew plenty of people who scored in the 1400-1600 range who loved Lord of the Rings above all else.
Of course, this might be skewed by the high school I went to -- Enloe was the top magnet high school in the country when my wife and I were there. I was actually a bit embarrassed by my 1425, and with a ~4.4 weighted GPA, I was only something like 125th in my class of about 500. My wife had a much, much higher weighted GPA, and a much better class rank in her year, but I think she'd rather I not publish those on the Internet.
The point is that I don't think that the books we read (within reason) are necessarily indicative of intelligence or SAT scores, and certainly that kids shouldn't be discouraged from reading certain books because it will "make them dumb." Obviously there are benefits to reading thought-provoking works with an advanced vocabulary, but reading works of value that inspire you is also important. Great books are about people, relationships, and ethics (Harry Potter and Ender's Game) as often as they are about deep ideas in an academic sense. Read higher-class literature if that's what moves you, but don't expect that to be a primary determinant of your academic success.