Nov. 8 1971 - Led Zeppelin IV
July 12, 1971 - Funkadelic - Maggot Brain
and in regards to the 70's have a lack of talent, please consider a few albums by Neil Young, Bowie's Berlin years, the bulk of Pink Floyd's work, American Beauty/Workingman's Dead, a few Al Green albums, Headhunters and Keith Jarret's Koln Concert. Off the top of my head.
re: 1989 - Paul's Boutique.