A tossup between Waterbending or Shapeshifting.
With the former, i'd have a degree of subpowers I could tap into (Blood Bending, Ice creation, Healing). Or, with the later I could fly or explore the world as I pleased. Who wouldn't want to try swimming in the ocean like a fish, or flying like a bird? And, depending upon how far I could go with the shapeshifting, I may be able to turn into a dinosaur or a dragon. That'd be pretty sweet.
With the former, i'd have a degree of subpowers I could tap into (Blood Bending, Ice creation, Healing). Or, with the later I could fly or explore the world as I pleased. Who wouldn't want to try swimming in the ocean like a fish, or flying like a bird? And, depending upon how far I could go with the shapeshifting, I may be able to turn into a dinosaur or a dragon. That'd be pretty sweet.