Great Thread! Santana Lotus has got to take the cake IMHO.
King Crimson "Lizard" "Wake of Posideon"
Also Moody Blues "Seventh Sojourn"
How about all of the very artistic graphic designs of the ECM jazz label during the 70's? very avante garde modernism.
Joe Jackson trying to look like Sonny Rollins on "Body and Soul"
The solo recordings of Anthony Phillips "private parts and pieces I,II,III" if not for the music, certainly for the covers.