Brave New World is my favourite one so far.
No one suggested you 1984 by Orwell... Maybe it's so famous that it's useless to mention it x-)
Another one is The Man in the High Castle by Philip Dick, basically it is the author's guesswork about how the world would have been if the Allies had lost WWII.
I also heard some people say that The Giver's trilogy by Lois Lowry is worth reading, but I still have to.
And finally, I think that also High Rise by J. G. Ballard may interest you. The novel is set in an ultra-modern high-rise building, the people living in it are like a society isolated from the outside world, but this society, due to some problems, starts degenerating.