Easy. I tend to lean towards books that are subtle social commentaries while still being enjoyable reading.
1984 - George Orwell - For the first glimpse into the future of humankind.
Oliver Twist - Charles Dickens - a Classic with a capital C. Needs no explanation!
Vanity Fair - William Makepeace Thakera - for being so intelligent, political, yet thoroughly entertaining
The Kite Runner - Khaled Husseini - a book that comes alive with cultural references. It gave me new eyes and I saw a new world.
The Inferno - Dante - because itll scare you into being good!(only kidding just a little!)