*head spinning*
I own about 1000 metal albums, and have probably listened to about 3-4000 (wild guess). It's just impossible to be so definitive. However, there are certain albums that will ALWAYS be revolutionary, at least in the way that I *personally* appreciate music. So it goes without saying that these albums are a given - in fact, just assume that these are carved in stone since my CD collection would be worthless without them (in no order):
Megadeth - Peace Sells, So Far So Good So What, Rust in Peace
Iron Maiden - s/t, Number of the Beast, Powerslave, Live After Death, Seventh Son
Queensryche - Operation Mindcrime
Sepultura - Beneath the Remains, Arise
Judas Priest - Painkiller
Mercyful Fate / King Diamond - Melissa, Don't Break the Oath, Abigail
Savatage - Gutter Ballet
Metallica - Kill 'em All, Ride the Lightning, Master of Puppets, And Justice for All
Yngwie J Malmsteen - Rising Force
Slayer - Reign in Blood
Black Sabbath - Master of Reality, Vol. 4, Sabbath Bloody Sabbath, Heaven and Hell
Ozzy Osbourne - Blizzard of Ozz, Diary of a Madman, Tribute, Bark at the Moon
I'm also drawing a line across heavy rock albums and therefore excluding anything from Led Zeppelin, Rainbow, Van Halen, Guns n' Roses, and The Cult. In particular, "III & Houses of the Holy", "Long Live Rock n Roll", "1984", "Appetite for Destruction" and "Sonic Temple" respectively are all 10/10 buy or die.
Right then, a more 'current' top 10 as follows (all 10/10 and earth shattering omg lick me dirty priest):
HAMMERS OF MISFORTUNE - The August Engine
HAMMERS OF MISFORTUNE - The Bastard
EMPEROR - In the Nightside Eclipse
FALKENBACH - Magni Blandinn Ok Megintiri
AGALLOCH - Pale Folklore
EMPYRIUM - Songs of Moors and Misty Fields
EMPYRIUM - Weiland
ANATHEMA - Serenades
PRIMORDIAL - Spirit the Earth Aflame
OPETH - Morningrise
And these flicker around the 9.5 - 9.9999/10 mark, so who's to say they couldn't be in the list come tomorrow...
EDGE OF SANITY "Crimson"
BLIND GUARDIAN "Nightfall in Middle Earth"
AETERNUS "And so the Night Became"
NEGURA BUNGET "'N Crugu Bradului"
AMORPHIS "Elegy"
GAMMA RAY "Land of the Free"
EUCHARIST "Velvet Creation"
SUMMONING "Stronghold" (maybe "Dol Guldur" -- it keeps switching)
NOVEMBERS DOOM "The Knowing"
ULVER "Bergtatt" & "Kveldssanger"
WOLVERINE "Cold Light of Monday"
PESTILENCE "Testimony of the Ancients"
KING DIAMOND "Puppet Master"
And I don't know what to do with SWANS "The Great Annihilator". I don't listen to them with 'metal' ears, but I couldn't make this thread without their mention...
You see, it's just not possible to be so definitive around 10 albums, at least not when you're my age.