I'm a huge fan of Christian metal. Bands like Fit For A King, August Burns Red, Impending Doom, Wolves at the Gate, For Today, etc.
My favorite song of all time would have to be the single that Fit For A King just came out with. It's about a man who thinks that he can work his way into heaven by practically torturing himself (like the monks did) and he's crying out to God "This pain is just too much to take. Use me as Your servant or just let me go."
But God is crying back "You just need to have faith and then you will have grace."