Probably my absolute favorite book series are The Enchanted Forest Chronicles by Patricia C. Wrede. The protagonist is a princess who grows up hating all the typical princess things she's being taught so she convinces people to teach her swordfighting, magic, Latin, and other things princes are taught. When she gets fed up she runs away to be a dragon's princess and has all sorts of great adventures.

Those books are so refreshing and brilliant that I still reread them to this day.