I want to know why Pearl Jan is on that list. Used to like them but wouldn't call them pioneers or anything. Metallica would have to inch out Tool for me, though in their day Tool could create something of a religious experience. Metallica on the other hand is timeless. How can you not rock it out when you hear a song - speaking of which I could use a little Last Caress right about now... (that would be my badass Metallica face there)