It's not a guilty pleasure, I like power metal. Sure it's cheesy, so what? Most Black/Death metal bands have incredibly stupid lyrics and no one says anything because it's "aggressive" and "masculine". Bullshit.
So, power metal can be all about (most bands at least) fantasy, dragons, elves, dwarves, rainbows, etc... where's the big difference? To be honest with you, I prefer cheesy to stupid, but that's just me.