"Metallica’s music represented the darker side of life, one that “Christian” music tended to ignore."

Most 'Christian' music still doesn't. :P

It's a sad reality, that. Here we are, exploring the depths of God and what it means to live with Him, in Him, as we journey through this life. And the best music we can come up with are some poppy tunes with shallow lyrics.

I had a strange experience many years ago that could only have been experienced to understand. Nevertheless, it was still a big moment for me. I remember staring out at the sea at night, wondering about the despair of my life at that point (nothing tragic, but I was very lonely at the time) and saw the deep, dark, blackness of each wave as it crashed onto the shore. I had this awkward realisation: God is in the Black too. He is also there, in the deepest dark of our Universe. Something of the mystery of God struck me. He created night. And it was good. He makes all things good. God is just never exactly what we expect Him to be.