Mockingjay by Susanne Collins
By book three, of The Hunger Games, the Districts are in all out rebellion against the Capital. Collins stays true to her genre fiction roots here and gives us a properly dystopic (if shallow) political analysis.
Unlike the grand finale of the Twilight series (to which Hunger Games is often unfairly compared), this is not a bloodless resolution in which everyone walks away happy.
I enjoyed all three of these books, though the style and characters are both presented at a fourteen year old level. It is surprising and strange that mainstream tween fiction will also likely be the best (and most popular) dystopian sci-fi of the first decade of our brave new century.