I'll say Kyne's Peace, but only after you've got the Animal Allegiance shout. After that, I always use that one instead as it will actually place the creature on your side rather than just Calming it. I love when I can make a herd of mammoths attack their handlers or a nearby dragon.
I never use fire or frost breath much either, they're the same as using destruction magic only weaker and with an annoying cooldown.
Elemental Fury. Completely and utterly useless as it doesn't work on enchanted weapons of any kind.
I agree with this too. Was planning to use it when I was using bound weapons only to find it doesn't work with those either.

Maybe the better question is how many shouts are actually useful, so many are just novelty magic.
