I finished watching Avatar: The Last Airbender on Netflix yesterday. I took a screenshot of one of my favourite scenes of the final episode. Aang (the Avatar) is fighting the evil Fire Lord and he summons a sphere of air, water, fire, and earth which surrounds him.
I highly recommend this series to any who like fantasy stories. It's one of the best animated series I've seen, and it's as good as or better than some live action series I've seen.