Top 5 Power Metal Bands.

Adramelch
Helloween

And three bands that don't cut the power metal mustard by today's definitions (thankfully).
 
Helloween. I dont concider Children of Bodom power metal at all. If they had been, it would have been them by a milestone. But their not.
 
...or we can admit to ourselves that they're both bad and be done with it.

We could admit that... of course there's the fact that you're wrong; but I suppose we could admit that...

EDIT:

Kiuas is one of the most original and innovative power metal bands around today. They have the most unique vocalist in power metal (in my opinion) and some of the most talented musicians. They employ the "hard edge" power metal style, but they do it with class and ingenuity. They're an act to be reckoned with.
 
You might also want to check out Timeless Miracle. They may have been mentioned a while ago though I'm not totally sure but they're one of the best power bands I listened to tbh. The singer is awsome.
 
Helloween(with the excepetion of a few releases)
Gamma Ray(same deal with Helloween)
Primal Fear
Iced Earth
Kamelot
 
With melodic vocals, CoB would be power metal. Without it, they're melodeath. Pretty much end of discussion.

Man, my top 5 will be tough 'cause I refuse to include any of the bands that have gone weak in recent years (Sonata, Edguy, Freedom Call...)

Blind Guardian
Helloween
Gamma Ray
Falconer
DragonForce

*expects to get made fun of for that last one, but hell, I love 'em.*