Best of 2012
Moss Icon - Complete Discography

Okay, I'm cheating a bit here - this isn't an album but a discography compilation. Moss Icon was one of the best bands to play 80s-style emocore. Incredibly loud and abrasive, but with some surprisingly catchy hooks and melodies. Strongly recommended for any hardcore punk fans.
Honorable Mentions 2012
Alcest - Les voyages de l'âme

Simply one of my favorite bands ever. People call this "post-rock", "blackgaze", whatever... I call it dream music. Sublimely beautiful.
Les Discrets - Ariettes oubliées...

Looks like Alcest, sounds like Alcest, features members of Alcest... It's no surprise that I also adore this record.
Swans - The Seer

I really don't know how to describe Swans to someone who has never listened to them. A brutal and experimental record. Glad to see they're back together.
Swans - We Rose From Your Bed With the Sun in Our Head

As a general rule, I hate most live albums. They're generally released as cash-grabs or to fulfill record contract obligations. Not so with Swans - this features unreleased songs and retooled versions of the classics. Essential.
New Discoveries
Ragnarok - Arising Realm

Classic Norwegian black metal that I somehow skipped over back in the 1990s. Better late than never.
Unholy - The Second Ring of Power

I had always heard this band's name dropped in doom metal discussions, but I could never track down any of their albums. The band's second record (released in 1994, finally re-issued in 2011) is trippy, bizarre, almost hysterical at times. I dig it.
Desire - Infinity... A Timeless Journey Through an Emotional Dream

Holy mother, what a hilariously bad album title. Thank God the music is awesome - mid-90s death/doom in the vein of Anathema, My Dying Bride, Paradise Lost, etc. Another hidden gem.
Arcana Coelestia - Le mirage de l'idéal

Absurdly grandiose black metal/doom metal/neoclassical hybrid from this Italian band. The production is poor, everything sounds like a wall of noise, but the incredible atmosphere prevails.
Pan.Thy.Monium - Dawn of Dreams

Noisy, esoteric, Swedish death metal with keys, saxophones, and a 20 minute opening track. I love it.