King Crimson's Earthbound blew me away, its still on my regular playlist and its been almost 40 years [Robert Fripp actually hated it but thankfully went back and cleaned it up for our digital sanitary modern world].
Black Sabbath's Sabbath Bloody Sabbath, was groundbreaking in so many ways, I think it actually opened the minds and doors of many future groups like Metallica, Sepultura etc
Smashing Pumpkins Siamese Dreams just took me in another direction.