I agree.withoutaface said:Nineteen Eighty-Four by George Orwell. 'nuff said.
+Any of the philosophy books (mainly his meditations) of Rene Descartes (aka The 'I think therefore I am' guy)
+Heart of Darkness Joseph Conrad
+Noughts and Crosses Malorie Blackman (Teen stupid love story, but touched me)
+The Tenant Of Wildfell Hall- Anne Bronte
+Encyclopaedia of Snow- Sarah Emily Miano (Has its faults, but an interesting concept and a format I've never seen before)
+Paradise Lost- John Milton
EDIT: Of Mice and Men was also brilliant