Oh man, I read 1984 when I was like 12, I had NO IDEA what I was getting into, I found it on a bookshelf in the house and my dad was all "that is a good book to read, it is almost true" and I still don't trust patriotism.
That's not just "good," it is "classic." George Orwell is the Shakespeare of "hey Soviets, they're pretty scary huh" and then you read the book and keep hoping Winston Churchill will crash through a wall or something.
"Animal Farm" is another by the same author, it's also really good, it's the history of Stalinism.
Others in that genre...
"Farenheit 451" by... uh, Bradbury? I'm not sure who wrote 451F, but it has a much "happier" ending.
"Brave New World" by Aldous Huxley is also good, I'm not sure whether it's more or less terrifying now that you read the sciencey bits and are all, "ha ha, that's totally not how designer babies are made."
Those are the ones that I can recall reading off the top of my head. They're good for reminding you that people are scary.
What am I reading right now?
I've actually been reading alot of books lately, on account of a discount bookstore going into a plaza down the street from my apartment.
"All of an Instant" by... G-something. It was pretty good, it was about the development of time travel and subsequent war to control human destiny. Anything dealing with timetravel can get bogged down really fast, but it does a really good job of explaining itself, I had no trouble following the goings on.
"The Elegant Solution" or something like that, about the Polio vaccine. It had some really spectacular lines, "soon the poliovirus would face the wrath of organized science." Good stuff.
"Argonaut" by Stanley Schmidt (editor of "Analog"). It was pretty good, definately a very thoughtful treatment of an interesting idea that was then ripped off by Star Trek. Fuckin' Trek-staff hacks.
Oh!
"Gregor the Overlander." It's a series of 5 books, children's literature, found the first three as a package in a wholesale club while I was waiting on a tire rotation. Anyway, I liked it enough to pick up 4 and 5 in Borders; lone 20-something in the Childrens' section scanning the shelves, nice!
Premise: Gregor, lower-class New Yorker (age 11), falls through a gateway to a pocket dimension, a huge cave system inhabited by huge, intelligent talking animals in addition to some human colonists from a few hundred years ago.
Anyway, it was a solid read and a lot of fun, I guess on this forum you'll understand it's an endorsement saying it made me want to write fanfiction about it.