9. Black Sabbath, 'Master of Reality'
Black Sabbath were on a roll when they cut Master of Reality in the summer of 1971. Their 1970 debut established them as one of the best new bands on the planet, and later that year they released Paranoid. Against all odds, that album actually put a couple of songs into heavy rotation on the radio. When it came time for Master of Reality they actually had a budget and more than a couple of days to record the thing. They used the time well, crafting riff-heavy masterpieces like "Children of the Grave," " Into the Void" and "Sweet Leaf." The songs seemed to pour out of them almost effortlessly at this point. Fans will endlessly debate when exactly Black Sabbath peaked, but one can make a strong argument it was right around the release of Master of Reality.