Deathspell Omega's 'Kénôse' EP - the release that catapulted them into still-untouchable realms.

And the only one l ever feel the need to listen to as well.  That's not to turn my nose up at their subsequent albums,  it's just that they don't seem to hold my attention. Kénôse is so tightly focused and just about the right length for my attention span. An hour of chaotic DsO gear is too much for me to take.

Revisited the 'Drought' EP recently, too, with a pair of good headphones. Stellar work.