"O Come, O Come, Emmanuel"
By
Iron Sharpens Iron, a Christian heavy metal (former?) band from southern California.
I'm not a metalhead by any stretch of the imagination. But I've been looking for high-quality modern adaptations of Advent hymns lately (easier said than done), and this one is actually really good.
And, if you play guitar, is there anything more satisfying than playing a song in the key of E-minor? Oh yeah, there is: dropping the low string down a whole-step, then turning the whole guitar down a half-step, such that you're now playing in Drop D-flat.