The Legend of Korra, the continuation of Avatar: The Last Airbender is a great series in itself, but no doubt one of the best things about it is the merging of science fiction and fantasy, actually the science fiction might of something resembling steampunk tech to the magic of the elemental power wielded by the benders and the avatar herself.
I assume the magic or fantasy part is clear but I'll describe it briefly. In the Legend of Korra world there are benders who are able to control the four elements, fire, earth, water and air. This is a little weird because this is the European version of the elements as the Chinese version is a little different. The Chinese have five elements: Metal, wood, earth, water and fire. And the Legend Of Korra takes place in a beautiful Chinese setting. Oh well.
Anyway, these benders are born with the ability to control one of the four elements. They have to practice to master their ability and the master benders are truly awesome, able to control huge waves, create lightning from their hands or hurl hurricanes of air towards the foes. Another interesting concept is that the benders control their powers through Kung Fu, with different arts like Taichi and Shaolin Kung Fu representing different elements.