I could never, no matter how much I tried or how much time I had, narrow my choice for one "best album". The thought of doing so can't even enter my mind.
First of all, I listen to 3 main genres, each has several subgenres. There are quite a few (to say the least) masterpieces in each genre and subgenre that I feel are equal in artistic, emotional, and intellectual content, to many pieces in the sane genre, and other genres and subgenres.
The 3 genres I listen to are:
Jazz, which includes: post bop, fusion, chamber jazz, M-Base, avant-garde.
Prog, which includes: Canterbury, classic prog, Zeuhl, avan-prog, prog-metal.
Classical, which includes: avant-garde, serial, atonal, dissonant, spectralism, mostly from the post 1950's. The 'thorny' sounding stuff.😎
The best I could ever hope to do, would be to pick, say 10 from each genre, and even that wouldn't cover it. So, prepare for a major cheat!
Here goes:
Prog:
Yes - Close to the Edge
Genesis - The Lamb Lies Down on Broadway
PFM - Per un Amico
Thinking Plague - The History of Madness
Magma - K.A.
King Crimson - Larks' Tongues in Aspic
Anglagard - Hybris
Gentle Giant - Octopus
Banco - Io Sono Nato Libero
National Health - Of Queues and Cures
Classical:
Elliott Carter - Concerto for orchestra
Charles Wuorinen - 4th Piano concerto
Joan Tower - Concerto for orchestra
Magnus Lindberg - Sculpture
Bartok - Music for strings, percussion, and celesta
Krzysztof Penderecki - Violin Concerto No. 2: Metamorphosen
Ernst Krenek - Static and Ecstatic
Stravinsky - The Rite of Spring
Alban Berg - Violin Concerto
Bruno Maderna - 3rd Oboe concerto
Jazz:
Miles - In a Silent Way
Coltrane - A Love Supreme
Mahavishnu Orchestra - Inner Mounting Flame
Return to Forever - Romantic Warrior
The Art Ensemble of Chicago - Full Force
Pharoah Sanders - Africa
Steve Coleman's Natal Eclipse - Morphogenesis
Oregon - Out of the Woods
Keith Jarratt - Koln
Anthony Braxton - Seven Compositions