Dystopias not on the wikipedia list:
The Gate to Woman's Country, by Sherri Tepper (actually, many of her books qualify as dystopias),
The City of Ember by Jeanne DuPrau (and its sequels),
The Weapon Shops of Isher by A.E. Van Vogt, the Tripods trilogy by John Christopher. A related category is apocolyptic fiction (end of the world stuff). Asimov, Greenberg and Waugh edited a great anthology titled
Catastrophies that covers the spectrum from end of the universe to end of human civilization as we know it. For something a little different, try
The Clowns of God By Morris West.
In re-reading my own post, I realize that I have a preference for dystopias in which the conflict is resolved, as opposed to the more "classic" dystopia in which the hero fails to affect the society and the conflict remains unresolved. Your mileage may vary, naturally.
