Making my own list based on what albums I think are the best from each sub-genre out of what I've heard so far.
Trad Metal
Judas Priest - Sad Wings of Destiny, Sin After Sin, Stained Class, British Steel, Screaming For Vengeance, and Defenders of the Faith
Black Sabbath - self-titled - Sabotage and Heaven & Hell and Mob Rules
Dio - Holy Diver
Accept - Balls To the Wild and Restless and Wild
Twisted Sister - Under the Blade and Stay Hungry (Twisted Sister is not glam.)
Skid Row - Slave to the Grind
NWOBHM
Iron Maiden - self-titled - Seventh Son of a Seventh Son
Def Leppard - On Through the Night (Seriously, listen to it, it's good.)
Diamond Head - Lightning to the Nations
Glam Metal (We forgot glam. Many people here don't like glam, but it was pretty important in metal history.)
Motley Crue - Too Fast For Love and Shout at the Devil
Skid Row - self-titled
Dokken - Tooth & Nail and Under Lock and Key
Bon Jovi - Slippery When Wet
Europe - The Final Countdown and Out of This World
Ratt - Out of the Cellar
Def Leppard - Pyromania and Hysteria
Speed Metal (we forgot speed metal too, unless it's being merged in with either traditonal metal or thrash.)
Judas Priest - Painkiller
Exciter - Heavy Metal Maniac and Violence and Force
Blind Guardian - Battalions of Fear
Rage - Perfect Man
Helloween - Walls of Jehrico
Thrash Metal
German Thrash Metal
Kreator - Endless Pain, Pleasure to Kill, and Coma of Souls
Soodm - Persecution Mania and Agent Orange
LA Thrash Metal
Metallica - Kill 'Em All, Ride the Lightning, and Master of Puppets
Megadeth - Peace Sells - Countdown to Extinction
Slayer - Show No Mercy - South of Heaven
Exodus - Bonded By Blood, Fabulous Disaster, and Impact is Imminent (underrated album)
Testament - The Legacy and The New Order
Vio-lence - Eternal Nightmare and Oppressing the Masses
Dark Angel - Darkness Descends
Heathen - Breaking the Silence and Victims of Deception
Metal Church - self-titled - Blessing in Disguise
Other Thrash
Overkill - Feel the Fire - Horrorscope
Anthrax - Spreading the Disease and Persistance of Time
Sepultura - Beneath the Remains
Death Metal
Death - Scream Bloddy Gore and Spritual Healing
Obituary - Cause of Death
Death/thrash
Possessed - Seven Churches
Sepultura - Schizophenia
Progressive Death Metal
Death - Human - Sound of Preserverance
Atheist - Piece of Time - Elements
Melodic Death Metal
Gothenburg
In Flames - Lunar Strain - Colony
Dark Tranquillity - Skydancer
Proto-Black Metal
Bathory - Self-titled and Return of Darkness and Evil
Sodom - In the Sign of Evil
Venom - Welcome to Hell and Black Metal
"Flower" Power Metal
Sonata Arctica - Ecliptica - Reckoning Night
Twilightning - Delirium Veil
Stratovarius - Visions
Helloween - Both Keeper albums
Dragonforce - Sonic Firestorm (eh, I dig it.)
True/thrashy Power Metal
Gamma Ray - Somewhere Out in Space - No World Order
Blind Guardian - Imaginations From the Other Side
Fates Warning - all of their 80s albums
Firewind - Between Heaven & Hell - Allgiance
Metal Church - Blessing in Disguise