I love this topic. So many things I want to recommend, but let's just go for a variety pack.
First off, something I just picked up again.
Siddhartha - Hermann Hesse. It's a short book, but a great read. Some of the good books recommended by other CAG's are very long so this is a good brisk read. I read it last in 8th or or 9th grade and didn't connect to it. Much more poignant in adult years.
2001: A Space Odyssey by Arthur C Clarke. Even though it was written simultaneously with the movie, it still holds true to "book much better than the film version". It was a book that I got sucked into.
Good Omens: Terry Pratchett and Neil Gaiman. Another religious base with the anti-christ and the apocalypse but with a great skewering tone. It's hilarious even with it's overtones and manages to not be preachy.
Ultimate History of Video Games by Steven L Kent. Yes, videogames are undoubtedly pop culture nowadays, but this book gives a good telling of the real history behind the craze. Good to have some solid knowledge on the culture instead of just playing games.
amazing.