Most of the music that I purchased in the 60s & 70s was either heavy rock (Black Sabbath, Deep Purple, Led Zeppelin etc) or folk-rock (Fairport Convention, Strawbs, Pentangle etc) but I did buy this album of Simon and Garfunkle.
Black Sabbath, 'Master of Reality' - The greatest sludge-metal band of them all in its prime. Paranoid may have bigger hits, but Master of Reality, released a mere six months later, is heavier. The highlight is "Sweet Leaf," a droning love song to marijuana. But the vibe is perfectly summed up by the final track, "Into the Void."