I think anyone who was listening to metal in the early 1990s will agree that it was the gateway album that brought them from more mainstream stuff like Metallica and Megadeth and the more extreme stuff like Cannibal Corpse.
01/18 & 01/19 -- Godspeed You! Black Emperor and Neurosis (in Montreal)
02/08 -- Dark Tranquility
04/11 -- Black Sabbath
04/24 -- Nile