Well, everyone should have known that Black Sabbath would make this list. Black Sabbath started it all. They were the very first metal band and their music became the framework for the doom metal genre. Their first five albums are utter classics. They wrote some of the most enduring metal songs of all time. There just really is not much more to say. Black Sabbath was the original. Everything we listen to now was made possible because of Black Sabbath.
As I mentioned, the first five albums with Ozzy Osbourne behind the mic are absolute classics. But even though the band went through a number of lineups (Tony Iommi is the only constant member), the band still managed to put out great albums with different singers. The material with Ronnie James Dio has gotten a lot of attention in recent years and the material with Tony Martin remains vastly underrated.
FAVORITE ALBUM: MASTER OF REALITY