Mockingjay. I just finished the Hunger Games and Girl on Fire last month. They are okay, though I think the first book was the best of the three (though I am only half-way through Mockingjay so far). I like some of the things about the books...but I certainly think they are way overrated based on how good I was told they are.
I was very disappointed with Girl on Fire and Mockingjay, but I respectfully disagree with your characterization of Hunger Games as overrated. It's the first fiction book to make a real impression on me in years. Highly recommended (IMO, of course).