it's a must read if you are a nerdfighter, it's a must read if you are a teenager, it's a must read if you like reading, it's a must read if you like great stories, and it's a must see if you happen to like pranks.
1984 by Orwell Harry Potter A Clockwork Orange The Fountainhead
I can't really think of anything else, but I am looking forward to seeing what other people put, I love finding out about books that I haven't read yet.
After reading some of the comments, I realized I left out everyone's favorite author John Green.
I'm an English Major, so this could be a long list.
Pride and Prejudice by Jane Austen.
Ulysses by James Joyce.
Franny and Zooey and Catcher in the Rye by J.D Salinger.
1984 by George Orwell.
The Faerie Queene by Edmund Spenser.
Homebody/Kabul by Tony Kushner. [play]
The Princess Bride by William Goldman.
Song of Myself by Walt Witman.
Harry Potter Series by J.K. Rowling.
Wrinkle in Time and Meet the Austins Series by Madeline L'Engle.
The Canturbury Tales by Geoffry Chaucer.
Macbeth and Midsummer Night's Dream by Shakespeare.
Tale of Two Cities by Charles Dickens.
Looking for Alaska and An Abundance of Katherines by John Green.
The Stickwife by Debora Cloud. [play]
How I Learned to Drive by Paula Vogel. [play]
The Laramie Project by Moises Kaufman. [play]
Paradise by Glen O'Mally. [play]
The Host by Stephenie Meyer.
Catch 22 by Joseph Heller.
One Flew Over the Cuckoo's Nest by Ken Kesey.
Galileo by Bertol Brecht. [play]
And so many more. SO many more. This list is WELL short.