I'd choose:
Hitchhiker's Guide To The Galaxy - Douglas Adams
Nineteen Eighty-Four - George Orwell
The Curious Incident of the Dog in the Night-Time - Mark Haddon
(this three from ejcot's list. I really love them)
[background=rgb(252, 252, 252)]Complete Works of William Shakespeare[/background]
(this is from wineguy list. I've never finished it, but in an island with plenty of time ...)
And then I'd add:
The Foundation Trilogy - Isaac Asimov
1Q84 - Haruki Murakami
El Aleph - Borges
The Clockwork Orange - Anthony Burgess
Cuentos Completos - Julio Cortazar
Brave New World - Aldous Huxley
oh seriously?
Catch-22 Joseph Heller
Trainspotting - Irvine Welsh
Hitchhiker's Guide To The Galaxy - Douglas Adams
Wasp Factory - Iain Banks
Nineteen Eighty-Four - George Orwell
The Curious Incident of the Dog in the Night-Time - Mark Haddon
Fight Club - Chuck Palahniuk
The World According to Garp - John Irving
One Flew Over the Cuckoo's Nest - Ken Kesey
Animal Farm - George Orwell