Black Sabbath, Paranoid (1970)
Originally titled War Pigs, the record company convinced Sabbath to change the name. They kept the cover of the acid trip cop in spandex with a sword and shield. That's their War Pig, the record company thought it would be interpretted as an anti war statement against the Vietnam War.
Blondie, Autoamerican (1980) & Plastic Letters (1978)
Sex Pistols, Never Mind The Bollocks, Here's The Sex Pistols (1977)
Miles Davis, Kind of Blue (1959)
Kind of Blue is not only one of the greatest jazz albums of all time, but it's also one of the most accessible albums for the non-jazz listener. John Coltrane plays sax, and Miles does something almost no one else could do...he makes trumpet sexy.
Lynyrd Skynyrd, Street Survivors (1977)
Most everyone knows about the plane crash that killed three members of Skynyrd. Street Surviviors was released within days of the tragedy. The original cover featured the band standing in flames, the record company and surviving members wisely changed it. I've included both. Incidentally rock lore has it that Aerosmith looked at buying the plane that went down but their manager passed on the deal. Aerosmith fired their manager because he didn't get them the plane.