Taken from: 32 Sci-Fi Novels You Should Read

32 books that have pushed the boundaries of the genre...

http://howtosplitanatom.com/news/32-sci-fi-novels-you-should-read/

Of course, Asimov hits the first spot with: Foundation (s)
Philip K. Dick: Do Androids Dream of Electric Sheep? - Never read it before, I should...
George Orwell: Animal Farm
H.G. Wells: War of the worlds
Isaac Asimov: I Robot - Another hit from the good doctor
Larry Niven: Ringworld
Frank Herbert: Dune
.......