I enjoy finding my two young daughters books with strong female characters. The Paper Bag Princess by Robert N. Munsch is a great example. The eponomous princess stands up to dragons, saves the boy, and then realizes the boy is a jerk and dumps him. I love it!
The dragon is known for burning everything in its path, including princesses. However, not even fire breathing dragons can stop this princess. She's got some serious moxy. And she's a great role model for young girls.