Oryx and Crake by Margret Atwood- I personally found it to be mind-blowing and very intense.
If you are ok with reading a play I can recommend this one:
R.U.R. by Karel Capek
What about I am Legend? I haven't read the novel, but liked the movie.
I've heard about people really liking Ender's Game, but am not sure if it is Dsytopian or plain sci-fi. I also think it is a series of books, so it could keep you busy for a while.
What about Philip K. Dick novels? I think he basically invented the sci-fi genre and that at least some of his works are dystopian. The story Do Androids Dream of Electric Sheep?
is the novel that the Blade Runner movie was based on. I imagine though that it really depends on if you are ok on reading something very sci-fi.
If you like fantasy novels maybe have a look at Philip Pullman's His Dark Materials
trilogy. I read it ages ago and enjoyed it a lot.