3. Black Sabbath
Black Sabbath did heavy metal first, and they may have done it best. Has any metal group managed to improve on songs like "Children of the Grave," "Sabbath Bloody Sabbath" or "War Pigs?" The Birmingham band started in 1968, and by the early Seventies were introducing metal to people all over the planet. Frontman Ozzy Osbourne was pushed out in 1979, but they recruited Ronnie James Dio and immediately cut Heaven and Hell, inarguably one of their finest works. They've been through an insane number of singers and lineups since, but in 1997 Sabbath reunited the classic foursome for a triumphant series of reunion tours. Word is they are working on their first LP since 1978's Never Say Die!, but they have yet to confirm that.