This topic again??!! 17wil, you should have asked this question in a christian forum instead, and you can see the reaction.
As a Catholic myself, I'm not bothered about what others think about the music that I listen to. I also don't recall the church having any action on this issue, I don't remember priest telling us not to listen to Judas Priest or Iron Maiden during his homily.
But certain christian groups do use "rock/metal music is evil" as a leverage for their message to be "holy". I suggest you stay away from these. These are the same people who condemn more traditional religion as evil too.
It boils down to a personal choice, and how you would interpret the song. Do you subscribe to the dark side or the light side, the choice is yours.
If you use the song for evil, then to you it will be evil. If you use the song as a guard against the evils, then the song to you is good.
Is human more good than bad, or more bad than good. The answer is undeniably in your own heart.