Stryper, Whitecross, Jerusalem, and Neal Morse (though he's more progressive rock).
Also, I don't see why people can't see metal and Christianity going together. Catholics are very much against all forms of rock, yes, but most of us aren't filled with that much prejudices. Nothing in the Bible or the Christian faith states that you cannot listen to heavy metal. Yes, there is even metal worship.
I heard of them from one of my friends from church. My favorite Christian heavy metal band is Skillet, as i love there switching off between a male and female singer. Besides them, I also like Family Force 5, as they combine that sort of heavy metal feel with techno beats, which is evident in songs like Fever and Radiator.
i also like the bands Pillar, P.O.D., Relient K (not really metal but good), Kutless, Fireflight, RED, Flyleaf and Falling Up skilet is OK but highly overrated