Which is... The King of Attolia, by Megan Whalen Turner.
I have to say that I was surprised by how good this book was. It's the final book in a trilogy; I picked up the first book, The Thief, because of the recommendation by one of my former coworkers. While The Thief wasn't amazing enough to deserve the best book award, it was good enough to keep me reading. And boy was I glad I did.
After The Thief this trilogy only got better, culminating in the deliciousness that is The King of Attolia. I will attempt not to spoil too much of the overarching plot. But the gist of it is: There is a new king of Attolia, who used to be the celebrated master thief of another kingdom. But now he's trying to fit into the role of king (which he's unused to) and his new court hates him because they think he's incompetent. Of course he's totally just screwing with them, since he is Master-Thief-Extremo.
I love the excellent court intrigue and Gen's overall awesomeness. This is great work, especially for fantasy-kingdom-court fiction, especially for younger-adult fiction. In short, I highly highly highly recommend it.