I know people might give me crap for this, but I feel as if Axl Rose should get an honorable mention. He has one of the biggest singing ranges of all time with a range of six octaves. He can not only hit the notes across those octvaes, but can sing with a growl, screech, croon, smooth lilt, a lot of variety and a massive range. Not the best IMO, but one of the best. It's just a shame he is such a massive douche bag.