These are some of my favourites, you can see the full 100 here.
1984 by George Orwell & Atonement by Ian McEwan
Catch 22 by Joseph Heller & Robinson Crusoe by Daniel Defoe
Don Quixote by Miguel de Cervantes & The Picture of Dorian Gray by Oscar Wilde
The Good Soldier by Ford Madox Ford & Gulliver's Travels by Jonathan Swift
Haroun and the Sea of Stories by Salman Rushdie & (The Strange Case of) Dr. Jekyll & Mr. Hyde by Robert Louis Stevenson
Jude the Obscure by Thomas Hardy & L.A. Confidential by James Ellroy
The Book of Laughter and Forgetting by Milan Kundera & Little Women by Louise May Alcott
Lord of the Flies by William Golding & Moby Dick by Herman Melville
To Kill a Mockingbird by Harper Lee & Nostromo by Joseph Conrad
One Hundred Years of Solitude by Gabriel Garcia Marquez & On the Road by Jack Kerouac
A Passage to India by E. M. Forster & Tin Drum by Günter Grass
The Way We Live Now by Anthony Trollope & Ulysses by James Joyce
Last, but not least. Wuthering Heights by Emily Brontë
The covers are also available as posters. I think they're stunning, what do you think?