I admit that I watch a little too much TV. I start watching a show from the beginning and voraciously consume it to it's entirety. My embarrassing admission is that I spend most of my time (thanks to Netflix instant streaming) doing nothing creative but rather watching characters on a screen pretend to live more interesting lives. If I had to choose a favorite I would be stuck.
I've seen though, I can say with equal pride and self-consciousness, every episode of "Avatar: The Last Airbender" too many times to count on both hands. I think this can be easily related to the Joseph Campbell's idea of the monomyth, the hero's journey, which he explained in his book "Hero with a Thousand Faces".
The series is divided into three books (seasons) just as the hero's journey is divided into three parts. The first is departure in which the hero leaves the world that he or she knows, often answering a higher calling. For young Aang, the series' hero, becoming the Avatar means leaving the monks that have raised him to bring balance back to a world that has gone off kilter. He is reluctant, as many heroes often are, and runs away, submerges himself in an iceberg to stay safe during a storm, but does not reemerge for a hundred years. He has left the world from which he came and is forced to journey onward.

Photo Credit:AndroFire

The series follows Aang (and Sokka, Toph and Katara, helpers along his path) throughout his journey as he hurries toward the realization of his Avatar destiny - to master the elements and save the world. The second part of the hero journey is Initiation, which for Aang is full realization as an Avatar. Aang does not fully master the elements within the series (give the kid a break, he's only 12) but he does begin to grow as a person and discovers how to restore balance to the world. He goes through a multitude of trials which test his endurance and his spiritual strength and gains maturity as the series progresses. He is initiated in the final season of the series when he defeats Firelord Ozai.
Finally, the return. Aang can never go back one hundred years, but he has returned the world to it's former peace. For the hero to return is to bring his new knowledge back as well as to have become a "master of two worlds". Aang exemplifies this - he has achieved balance between a material and spiritual life, he lives in the present moment and does not fear the future or regret his past.
Aang's story is the journey of the hero, cartoon charm simply a bonus.