What clic should I read?

I am wanting to become a more well rounded, educated person, and while I am naturally smart (common sense) I tend to slack when it comes to 'educating' myself. Well, long story short, I want to become smarter, more knowledgeable of scholarly things, which is why I am wanting to start reading some clics that I've never read. I finished reading The Great Gatsby, because I had it from high school, and I actually understood it, and liked it! (I didnt really read the whole thing in high school-lol!) Anyway, I thought I would get some suggestions from the pros (you guys!) as to what I should pick up at the bookstore to read next. I want to be educated and well rounded. Thanks!