I'm completely in love with Leo Tolstoy, Anna Karenina was genius. But it took me almost 5 days to finish it, since I got constant cramps. I also suggest Fahrenheit 451 by Ray Bradbury. I know it's too high-school-ish, but I reread it all the time. What about Catch-22, or Don Quixote? I'm sorry I could not be of more help, but I'm only in 7th grade, albeit Honors. We're currently reading White Fang by Jack London, but I'd already read that in the 5th grade, ugh.