I've done it.... here we go by decades!
1970: BLACK SABBATH - Black Sabbath (as a reward for starting the genre, they really had no competition)
1971: ALICE COOPER - Killer
1972: ALICE COOPER - School's Out
1973: ALICE COOPER - Billion Dollar Babies
1974: QUEEN - Queen II
1975: RAINBOW - Ritchie Blackmore's Rainbow
1976: JUDAS PRIEST - Sad Wings of Destiny
1977: JUDAS PRIEST - Sin After Sin & MEAT LOAF - Bat Out of Hell
1978: RAINBOW - Long Live Rock n' Roll & BRUCE SPRINGSTEEN - Darkness on the Edge of Town
1979: JUDAS PRIEST - Unleashed in the East
Decades consideration: 1970 and 1979 had really no other choices for me, and since for lack of competition Judas Priest was basically winning four year straight, I removed Hell Bent from Leather from 1978 to give a shoutout for Bruce Springsteen, alongside with Rainbow that already won over Bruce's 1975 Born to Run.
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1980: IRON MAIDEN - Iron Maiden
1981: BLACK SABBATH - Mob Rules
1982: IRON MAIDEN - The Number of the Beast
1983: IRON MAIDEN - Piece of Mind
1984: METALLICA - Ride the Lightning
1985: HELLOWEEN - Walls of Jericho
1986: METALLICA - Master of Puppets
1987: HELLOWEEN - Keeper of the Seven Keys part I
1988: IRON MAIDEN - Seventh Son of a Seventh Son & HELLOWEEN - Keeper of the Seven Keys part II
1989: SAVATAGE - Gutter Ballet
Decades consideration: we all know how chock full of classics this era is. For example it's obvious that Operation Mindcrime is a masterpiece, but I decided to not give more than two awards per year. So many bands got the short end of the stick here, for example Manowar.
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1990: JUDAS PRIEST - Painkiller
1991: SAVATAGE - Streets: A Rock Opera & METALLICA - Metallica
1992: DREAM THEATER - Images and Words & BLIND GUARDIAN - Somewhere Far Beyond
1993: SAVATAGE - Edge of Thorns & MEAT LOAF - Bat Out of Hell II: Back into Hell
1994: DREAM THEATER - Awake
1995: RAGE - Black in Mind & BLIND GUARDIAN - Imaginations from the Other Side
1996: RAGE - End of All Days
1997: BRUCE DICKINSON - Accident of Birth
1998: BRUCE DICKINSON - The Chemical Wedding & BLIND GUARDIAN - Nightfall in Middle Earth
1999: DREAM THEATER - Scenes from a Memory
The rise of power metal. Stratovarius and Virgin Steele couldn't get a win, but they released so many great albums in the decade. Also shoutout for Iced Earth, they never bested an insane competition but Stormrider, Dark Sage and Something Wicked this Way Comes are awesome. 1998 was so ridiculously full of awesome album: the IE one, Rage'x XIII, Virgin Steele's Invictus...
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2000: IRON MAIDEN - Brave New World & TRANS SIBERIAN ORCHESTRA - Beethoven's Last Night
2001: AVANTASIA - The Metal Opera part I & KAMELOT - Karma
2002: BLIND GUARDIAN - A Night at the Opera & RAGE - Unity
2003: IRON MAIDEN - Dance of Death & KAMELOT - Epica
2004: THERION - Sirius B & Lemuria (released together)
2005: DREAM THEATER - Octavarium
2006: IRON MAIDEN - A Matter of Life and Death
2007: SONATA ARCTICA - Unia & HELLOWEEN - Gambling with the Devil
2008: AVANTASIA - The Scarecrow & ELVENKING - Two Tragedy Poets (...and a Caravan of Weird Figures)
2009: ELUVEITIE - Evocation I - The Arcane Dominion
Decades consideration: Some clear victories here, but once again my self imposed restraint to two albums left out many worthwile choices in the power / heavy / symphonic genre. At least a pure folk metal album won
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2010: BLIND GUARDIAN - At the Edge of Time
2011: NIGHTWISH - Imaginaerum
2012: ELVENKING - Era
2013: RAGE / LINGUA MORTIS ORCHESTRA - LMO
2014: ELVENKING - The Pagan Manifesto
2015: IRON MAIDEN - The Book of Souls
2016: AVANTASIA - Ghostlights
2017: RAGE - Seasons of the Black & ELVENKING - Secrets of the Magick Grimoire
2018: JUDAS PRIEST - Firepower & GHOST - Prequelle
2019: CELLAR DARLING - The Spell & ELVENKING - Reader of the Runes - Divination
2020: NIGHTWISH - Human || Nature
Decades consideration: once again, I would have loved to pay homage to some bands that never won, but the competition is tough and I felt there needed to be clear winners, rather than giving double awards every year
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2021 so far: THERION - Leviathan; predicted: HELLOWEEN - Helloween