Originally Posted by
Redundant
The obvious choice of book after those two is "Animal Farm" by George Orwell. Most people who know those books will recommend it for a reason.
That or Do Androids Dream of Electric Sheep?, aka Blade Runner by Philip K. Dick, and then perhaps his other classic The Man in the High Castle.
Then you have the other classics such as
The Demolished Man by Alfred Bester
The Dispossessed by Ursula K. LeGuin
We by Yevgeny Zamyatin
Fahrenheit 451 by Ray Bradbury
and A Clockwork Orange by Anthony Burgess