Suggest one obsure album we all should hear

Not really sure what qualifies as "obscure," as it is a relative term... but if you've only heard Springsteen's BTR and later albums, you're missing his best, imo:  The Wild, the Innocent, and the E Street Shuffle.

Or, when was the last time you heard John Denver...?  How about Rocky Mountain High album... 

Not really obscure if you're a Willie Nelson fan, but if you're not familiar, then: Red Headed Stranger or his gorgeous album Stardust... 

Simon and Garfunkle: Bookends.

And for you rockers, better than their BTO Greatest Hits album(s): Bachman Turner Overdrive: Not Fragile

T Rex: Electric Warrior

and I violated the question, which asked for one album.

Well, thanks, everybody, for the list... just mining this list is going to be a lot of fun.

one more, just one:

has a raw "spooky" quality >> Buddy Holly: From The Original Master Tapes

@wmbray123 

Thumbs up on Astral Weeks.  Much better album overall than Moondance.

Neil Diamond:  Stones

old album, and short but sweet... don't knock it til you've heard it