3. Ronnie James Dio, Black Sabbath

When Black Sabbath kicked Ozzy out of the group in 1979, many people said they were through. Yet Black Sabbath gained a second wind with the late Ronnie James Dio in the fold and their first album together, Heaven And Hell. Dio may have technically recorded only three studio albums and a live record in total while in Sabbath, but his work with Sabbath regained notoriety thanks to Heaven & Hell (which was essentially a Sabbath-Dio era reunion under a new moniker). And to this day, many consider Dio as the best singer in Sabbath, some even more than Ozzy.