Look, I won't waste your time with a lot of commentary on these. This list is compiled from me searching my collection for '2012' and figuring out which albums I was still excited about. I included direct links to download all of these albums. (I do this in the interest of promoting bands I love. If you're a copyright owner who wants me to take a link down, contact me at dmca@mylifeismetal.com.) There's also a Spotify playlist that has my favorite tracks from all these albums, although it's missing some essentials, like "Take The Mirror" from White Lung.
I could really talk your ear off about all these releases, but how about you just hit Play instead? If you download things, be polite and say "thanks", but also be sure to bitch me out about how you can't believe Pig Destroyer didn't make the cut, or whatever.
BEST OF 2012
'INDIE'
BEAR IN HEAVEN - I Love You, It's Cool (catchy psych-rock)
DEATH GRIPS - The Money Store (aggressive hip-hop with crazy beats, courtesy of Zach Hill)
GRIZZLY BEAR - Shields
METZ - Metz (post-punk from Canada, catchy as fuck)
*** WHITE LUNG** - Sorry (punk from Vancouver, this girl is MEAN)
CHILL
CHROMATICS - Kill For Love
CLAMS CASINO - Instrumental Mixtape 2
FLYING LOTUS - Until the Quiet Comes
HOLY OTHER - Held
HOW TO DRESS WELL - Total Loss
*** LORN** - Ask The Dust
SIMIAN MOBILE DISCO - Unpatterns
XXYYXX - XXYYXX
POST-ROCK
 *** GODSPEED YOU! BLACK EMPEROR** - Allelujah! Don't Bend! Ascend! (unexpected, and amazing.)CASPIAN - Waking Season (another solid, heavy post-rock album from these guys. "Gone in Bloom and Baugh" instantly became one of my favorite tracks of theirs)
METAL
 *** CONVERGE** - All We Love We Leave Behind (these guys get better and better. this album has a lot of 'thrash' elements to it, which are added in a unique way that few bands could pull off)ELDER - Spires Burn (not a full album, but some of the catchiest stoner metal tracks I've heard. check out if you want something bright and fun with sweet Sabbath-y riffs)
ENSLAVED - RIITIIR (I haven't enjoyed a progressive metal album this much for many, many years)
ERYN NON DAE - Meliora (intense from start to finish and just excellent all-around, check out if you like technical death metal)
GLASS CLOUD - The Royal Thousand (surprisingly good, catchy, non-lame metalcore band, feat. the guitarist from The Tony Danza Tapdance Extravaganza)
GOJIRA - L'Enfant Sauvage (one of the best melodic death bands around. I call them 'green metal' because they sing about saving the whales and being a good steward of this planet)
KEHLVIN - The Orchard of Forking Paths (doom/sludge with excellent riffs)
KRALLICE - Years Past Matter
LOMA PRIETA - I.V. (meanest screamo)
OLD MAN GLOOM - NO (supergroup: ex-Isis, Converge, Cave In)