IV > MoP
Zep's monster seller has a bit too much of the Fantasy going on, although "Black Dog" and "Four Sticks" seriously are solid Zeppelin. I was never really that much of a fan of Metallica, and while MoP did spark a better kind of Metal scene in The States after a too much Aqua Net was going around in The 80's, it still sounRAB a a bit too-forced and heavy handed.