Nirvana - Nevermind; for getting me into "Rock"
Metallica - Metallica; for getting me into Metal
Sepulture - ChaosAD; for getting me into extremer Metal
Dissection - Storm; for getting me into Black/Death
haven't been listening to any of these releases for ages but they were my stepping stones...
Most important album "of all time": somehow Devin Townsends "Terria" - the perfect mixture between aggression and endless emotion