Everyone else is posting a list, why shouldn't I?
Thrash Metal
Megadeth
Slayer (Reign in Blood only)
Destroyer 666
Meshuggah
Overkill
Kreator
Anthrax
Sodom
S.O.D
Prong
Sadus
Sepultura (Arise, Beneath the Remains, Chaos AD, Schizophrenia)
Testament
Coroner
Arillery
Nuclear Assault
Exodus
Annihilator
Pantera
Exhorder
Vio-Lence
White Zombie
Pissing Razors
Machine Head (Burn my Eyes, and sort of the Burning Red, stfu)
Metallica (It pains me to say)
I stuck Groove Metal in there because Groove=Mid Paced Thrash :P
Death Metal
Death
Cynic
Morbid Angel
Cannibal Corpse (with Barnes only)
Master
Control Denied
Deicide
Behemoth
Carcass
Napalm Death (New Stuff is pure Death Metal)
Decapitation
Suffocation
Cephalic Carnage
Hypocrisy
Dismembered
Athiest
Malevolent Creation
Nile
Necophagist
Immolation
Cryptopsy
Gorguts
Dying Fetus (lol@wiggercore)
Opeth
Krisiun
Disgorge
Obituary
Pestilence
Penetralia
Black Metal
Naglfar
Nazgul
Mayhem
Darkthrone
Rotting Christ
Dark Funeral
Celtic Frost
Bathory
Xasthur
Immortal (True metal :D)
Gorgoroth
Emperor
Deathspell Omega
Akercocke
Anaal Nathrakh
Belphegor
Dissection
Agalloch
Drudkh
Goatwhore
Enslaved
Leviathan
Doom Metal
Pentagram
St. Vitus
Black Sabbath (I consider them Doom metal STFU)
Candlemass
Reverend Bizarre
Katatonia
Paradise Lost (first 2 albums only)
Funeral
Sunn O))) (Much Luff)
Earth
Khanate
Lotus Eaters
Burning Witch
Cathedral
Sleep
YOB
High On Fire
Avant-Garde Metal (my favorite)
Arcturus
Carnival In Coal
Faith No More
The Melvins (Although Sludge as well)
Ved Buens Ende
..And Oceans (first album)
Mr. Bungle (AHA)
Fantomas (Mike Patton, A genius)
Diabolical Masquerade
Virus
Ulver
In the Woods...
Beyond Dawn
Alchemist
Lux Occulta (later work)
Sludge Metal
Eyehategod
Crowbar
Down
The Melvins (again... :D)
Acid Bath (They will rock your cock)
Pelican
Isis
Neurosis
Electric Wizard
Fudge Tunnel (THEY ARE METAL)
Soilent Green
Cult of Luna
Boris
Bongzilla
Corrosion of Conformity
Iron Monkey (Awesomeness)
Mastodon (not metalcore)
Prog Metal
Dream Theater
Opeth (again)
Pain of Salvation
King's X
Liquid Tension Experiment
Devin Townsend Band (:D)
Rush (METAL)
Shadow Gallery
Spiral Architect
Spastic Ink
not too keen on Prog
Power Metal
Iced Earth
Iron Maiden
Eidolon
Firewind
Helloween
Rhapsody (Screw the "of Fire")
Cellador (New band, awesome)
Hammferfall
Blind Guardian
Demons and Wizards
Not too keen on power metal either
Industrial Metal
Ministry
Strapping Young Lad
Godflesh (Innovators BITCHES)
Young Gods
The Swamp Terrorists
The Berzerker
Circle of Dust
Jesu (beautiful work by our lord and master Justin Broaderick)
Fear Factory
Red Harvest
The Kovenant
Godhead
Head of David
I like industrial music, but not enough industrial metal bands that I know
Grindcore
Nasum
Napalm Death
Terrorizer
Sore Throat (hardcore but whatever)
Repulsion
Pig Destroyer
DRI
Brutal Truth
GUT
Anal Cunt (they rofl my lmao)
SOB
the only "metallic" grindcore I can think of.
That's my updated list.