Not much a Children of Bodom fan, Heavenduff, but Ensiferum are pretty great.(i never thought of them, tho when we were mentioning this)
I'll be sure to check out those others you suggested as well. I like most kinds of music, though the more poppy the music, the less likelihood I have of liking it. But I'm sure there's some I'll like of power metal.
Fun fact:
Pantera originated as a power metal group as well. They moved into a more aggressive metal sound later on, but you can still see glimpses, such as in the song "cemetary gates." He even goes into high-register at one point in the song. I found that interesting.