[Black Sabbath] – Black Sabbath, Paranoid, Masters of Reality (Classic metal)
[Judas Priest] – British Steel, Screaming for Vengeance, Painkiller (Classic metal, speed metal)
[Motorhead] – Icon (Speed metal)
[Venom] Welcome to Hell, Black Metal (Extreme speed metal)
[Queensryche] Operation Mindcrime (Trad metal/Progressive metal); FANTASTIC ALBUM
[Death] – any, but Scream Bloody Gore and Human are good places to start (Death Metal early career, progressive/tech-death metal later career) NOTE: These guys are credited as the very first death metal band
[Carcass] Heartwork, Surgical Steel (Melodic death metal)
[Dark Tranquility] Damage Done (Melodic death metal)
[Lost Horizon] – A Flame to the Ground Beneath (Power metal/progressive metal)
[Sonata Arctica] – Reckoning Night (Power metal)
[Iced Earth] The Blessed and the Damned (U.S. Power Metal/some Thrash metal)
[Cradle of Filth] Midian (Extreme gothic metal)
[Wolves in the Throne Room] Black Cascade, Celestial Lineage (U.S. Atmospheric black metal)
[Emperor] In the Nightside Eclipse, IX Equilibrium (Symphonic black metal)
[Metallica] anything from the 1980's (Thrash metal)
[Prong] Beg To Differ, Prove You Wrong, Cleansing (B.T.D is thrash metal, the other two are groove metal)
[Pantera] anything from 1990 to 2000, especially Vulgar Display Of Power (Groove metal)
[Exhorder] Slaughter in the Vatican, The Law (Groove Metal/thrash metal)
[Machine Head] any except The Burning Red and Supercharger; I highly recommend Burn My Eyes, The Blackening, and Unto The Locust (Groove metal/thrash metal)
[Slayer] Reign In Blood, Seasons In The Abyss, Divine Intervention (Thrash metal)
[Rhapsody] – Tales From The Emerald Sword Saga (Symphonic power metal)
[Nightwish] – Oceanborn, Century Child (Symphonic metal w/female vocals)
[Symphony X] Paradise Lost (Progressive Metal)
[Dream Theater] Images & Words, Awake, Metropolis Pt2 (Progressive metal); A Change Of Seasons is their best song, IMO.
[Tystnaden] Sham of Perfection (Gothic metal w/female vocals)
[Nevermore] Dead Heart In A Dead World, This Godless Endeavor (Progressive groove metal)
[Sepultura] any with Max Cavalera on vocals except Roots. Dante XXI and The Mediator are also great albums. (Thrash metal/death metal early material; later material is groove metal)
[A Storm of Light] And We Wept the Black Ocean Within (Post-metal/doom metal)
[High On Fire] Snakes of the Divine, De Vermis Mysteriis (Stoner metal/sludge metal)
[Mastodon] Leviathan (Progressive sludge metal)
[Bolt Thrower] anything from War Master onwards (Death metal)
[Mayhem] De Mysteriis Dom Sathanas (Black metal)
[Drudkh] Autumn Aurora, Eternal Turn of the Wheel (Atmospheric black metal)
[Overkill] Ironbound, Horrorscope (Thrash metal)
[Saint Vitus] Mournful Cries (Doom metal)
[Iron Maiden] Number of the Beast, Powerslave, Seventh Son of a Seventh Son (Traditional heavy metal)
[Kamelot] The Black Halo (Symphonic power metal)
[Black Breath] Sentenced to Life (kind of a genre mix of Black metal/speed metal/crust punk/hardcore punk/death metal instrumentally, vocalist screams a lot, so this might not be for you)
[Kreator] Pleasure to Kill (Thrash metal/extreme metal)
[Fear Factory] Demanufacture, Obsolete (Industrial groove metal/some thrash and death influences)
[Vader] Litany (Death metal)
[Amon Amarth] With Oden On Our Side, Twilight of the Thunder God, Surtur Rising (Melodic death metal)
[Heaven & Hell] The Devil You Know (Traditional heavy metal/probably a little doom metal)
[Razor] Violent Restitution (Thrash metal)
[Taake] Nattestid Ser Porten Vid (Black metal)
[Destruction] Eternal Devastation (Thrash metal)
[Meshuggah] Destroy Erase Improve (Experimental extreme metal/progressive metal/groove metal)
[Agalloch] Pale Folklore (They're a mix of Folk metal, post-metal, black metal, doom metal, and various other subgenres)
[Eluveitie] Everything Remains As It Never Was, Origins (Folk metal/melodic death metal)
[Enslaved] Mardraum (Black metal/progressive metal)
[Byzantine] ...And They Shall Take Up Serpents (Groove metal/progressive metal)
[Immortal] Diabolical Fullmoon Mysticism (Black metal)
[Prostitute] Vaginal Hell Demos (Sludge metal/stoner metal)
[Candlemass] Epicus Doomicus Metallicus (Doom metal)
[Soulfly] Dark Ages, Enslaved (Groove metal/thrash metal)
[Fool's Game] Reality Divine (Power metal/groove metal?)
[Exodus] Bonded By Blood, Blood In Blood Out (Thrash metal)
[SepticFlesh] Titan (Symphonic death metal)
[Behemoth] The Satanist (Black metal)
[Incursed] Elderslied (Folk metal)
[Ne Obliviscaris] Citadel (Extreme progressive metal/melodic death metal)
[Orphaned Land] Mabool (Progressive metal/folk metal/death metal)
[Battle Beast] Unholy Savior (Power Metal)
[Angra] Secret Garden (Symphonic metal/folk metal/power metal)
[Anaal Nathrakh] Total Fucking Necro (Black metal)
[Amorphis] Tales From A Thousand Lakes (Death metal/folk metal)
[At The Gates] Slaughter Of The Soul (Melodic death metal)
[Metal Church] Metal Church (Thrash metal/trad metal)
[Mirrorthrone] Gangrene (Symphonic extreme metal)
[Obituary] Cause of Death, Slowly We Rot (Death metal)
[Samael] Passage, Exodus (Symphonic black metal/industrial metal)
[Savatage] Hall Of The Mountain King (Power metal/ heavy metal)
[Satyricon] Dark Medieval Times (Black metal)
[Arcturus] Arcturian (Avant-garde metal, symphonic black metal)
[Accept] Restless and Wild, Balls To The Wall (Speed metal)