My response was
Now I'm pondering the meaning of "dystopia". I'm not sure that bleak is necessarily a part of it, but I've always included things like "vague sense of menace" and "dictatorial rule" (be it theological, ideological or by machine). Sooo... Planet of the Apes would go into my definition. As would England, England (which has some very funny moments).
And, I'd have to say "yes" to Gathering Blue and Messenger - the society is closed, somewhat primitive, and there's that sense of menace from something/someone. I'll even throw in City of Ember for the same reasons.
As for them stacking up to 1984 or Brave New World, I think that's because Orwell and Huxley were writing in response to what they saw as real menaces in their real world, whereas these newer (and aimed at a younger audience) books are simply what C.S. Lewis might term a "supposal".
Also added to the list? The Giver, The Lottery and The Children of Men. I know that's a very small list, and that there are many, many others that should be on there. However, I mention them to raise the questions Fairrosa asked: what is a dystopian novel? how do we define it? and is it a sub-genre unto itself?