There is an interesting power metal band from Germany. The style is power metal similar to Theocracy, but without any bass, guitars or keyboards. A capella power metal. Actually I've never heard anything similar.
Check out their video "The mission" at http://www.vancanto.de/
I was on the Theocracy forums and saw this and figured I'd share it over here too, they also have a myspace you can check out.
http://www.myspace.com/vancanto
What do you think? Im still trying to gather my opinion, but so far all I can say is "its awesome."