Great Expectations by Charles Dickens
The Great Gatsby by F. Scott Fitzgerald
Lord of the Flies by William Golding
A Separate Peace by John Knowles
The Invisible Man by H.G. Wells
Brave New World by Aldous Huxley

and I'm not sure if this one is really a 'classic' but it is one of my favorite books...
Lolita by Vladimir Nabacov