Brave New World, by Aldous Huxley (pub. 1932)

A Clockwork Orange, by Anthony Burgess (pub. 1962)

The Demolished Man, by Alfred Bester (pub. 1953)

Dhalgren, by Samuel R. Delaney (pub. 1975)

It Can't Happen Here, by Sinclair Lewis (pub. 1935)

Native Tongue, by Suzette Haden Elgin (pub. 1984)

Never Let Me Go, by Kazuo Ishiguro (pub. 2005)

Philip K. Dick
I don't think I've read any of his stuff, but I've seen some movies based on his writing. And I imagine his books or short stories are probably better than the movies, so I should check them out sometime.

Saint Leibowitz and the Wild Horse Woman, by Walter M. Miller, Jr. (pub. 1997)
This is a sequel to "A Canticle for Leibowitz," which I'm sure I quite liked, but I don't remember it very well. So I'd wand to reread that before this.

Snow Crash, by Neal Stephenson (pub. 1992)

Station Eleven, by Emily St. John Mandel (pub. 2014)

We, by Yevgeny Zamyatin (pub. 1924)

The Windup Girl, by Paolo Bacigalupi (pub. 2009)