I’ll start first, it’s Once Sent From The Golden Hall. I’m also open to discussion about said albums!
Master of Puppets. I know it’s not a particularly daring choice, but I don’t care, it’s perfection.
Blackwater Park by Opeth
Hard to pick a single one, so I’ll just list a few ones that I keep going back to.
Dream Theater - Awake
Destiny Potato - Lun
Fear Factory - Digimortal
In Flames - Clayman
Too many, and not all of them are metal. But, sticking with the theme of the community…
Megadeth - Rust In Peace
Suffocation - Pierced From Within
At The Gates - Slaughter of the Soul
Gorgasm - Masticate To Dominate
Metallica - Ride The Lightning
Slayer - Decade Of Aggression
Pantera - 101 Proof
Dream Theater - Train Of Thought
Nile - Amongst The Catacombs of Nephren-Ka
Panzerchrist - Soul Collector
Morbid Angel - Altars of Madness
Dying Fetus - Stop At Nothing
Burzum - Filosofem
Sepultura - Chaos A.D.
There are more polished albums, I’ll grant you, but it was the first one I heard and still seems to be the one I constantly return to, so I figure it’s my favorite of theirs. For better or worse!
In my list I was having a hard time choosing between Awake and ToT. I also love Met.Pt.2 luke that other guy posted, but I find these two album just a notch above in terms of individual songs.
It’s hard to just pick one but my favorite is probably Chaos A.D.