Roger Dean did some incredible art work for all the early Yes albums I like all of them.
Always liked the cover for Who's Next by The Who.
The album cover shows a photograph, taken at Easington Colliery, of the band apparently having just urinated on a large concrete piling protruding from a slag heap. According to photographer Ethan A. Russell, most of the members were unable to urinate, so rainwater was tipped from an empty film canister to achieve the desired effect. The photo is often seen to be a reference to the monolith discovered on the moon in the film 2001: A Space Odyssey, which had been released only about three years earlier. In 2003, the United States cable television channel VH1 named Who's Next's front cover the second greatest album cover of all time.