Fascinating question (and I'm eternally grateful to have discovered Eve Babitz here--I knew most of these albums but not her authorship).

My favorite cover is probably Billy Tipton Plays Hi Fi on Piano, not for the artwork or text but for the subtext. Check out a Billy Tipton bio if you don't know his work. Hint: the man on the cover ogling the decollete women is a woman.

Click on More Images from the Discogs site to read the back cover. 1950's in a nutshell. https://www.discogs.com/release/5566311-Billy-Tipton-Billy-Tipton-Plays-Hi-Fi-On-Piano-

I found a cover without the actual record at a thrift store and bought it immediately.

Favorite album cover as artwork is probably Keynsham by the Bonzo Dog Band.