I have to say that DragonForce is a pretty k-rad group - so much so that, apparently, they are a reasonable substitute for scandium on the periodic table of the elements. I've not had much experience with power metal bands, but the epic nature of DragonForce's lyrics really set up their songs as things apart. Beyond that, they have way more meaning than the standard popular shlock that is 99.5% about love.
Their song My Spirit Will Go On, in particular, captures my attention. Though the music is fast and active, the lyrics are rather dark, and in my opinion capture what will probably be ahead of us in the next ninety years. It's one of those songs that can have a lot read into the framework - personally, the way I read it, the demon is carbon dioxide.