Regarding the list: I thought it was alright for 70s and then quickly went off the rails.
Pretty much.
Here are my choices up through 1992 (obviously, the competition in the early 70s was pretty thin, and the definition of "metal" changes over the years):
1970: Black Sabbath - "War Pigs" ("Black Sabbath" isn't a bad choice, but at least a couple songs on
Paranoid are, IMO, better)
1971: Black Sabbath - "Children of the Grave"
1972: Deep Purple - "Highway Star"
1973: Black Sabbath - "Sabbath Bloody Sabbath" (maybe my favorite Ozzy era Sabbath song)
1974: UFO - "Rock Bottom" (this is the first year where the choice is difficult; "Burn" and "Working Man" are very close seconds)
1975: Rush - "By-Tor and the Snow Dog"
1976: Rainbow - "Stargazer" (REALLY hard not to pick "Achilles Last Stand" or "2112")
1977: Scorpions - "Sails of Charon" ("Lights Out" is a close second)
1978: Judas Priest - "Hell Bent for Leather" or "Running Wild" (can't decide)
1979: Triumph - "Lay It on the Line"
1980: Black Sabbath - "Heaven and Hell" (this is where the REALLY tough competition begins; I could easily have picked "Phantom of the Opera" or "Revelation: Mother Earth")
1981: Ozzy Osbourne - "Diary of a Madman" (by a hair over Sabbath's "Falling off the Edge of the World"
1982: Iron Maiden - "The Number of the Beast" (MANY very close seconds)
1983: Iron Maiden - "To Tame a Land" (impossible not to pick my favorite Maiden song of all time)
1984: Judas Priest - "The Sentinel" (and my favorite Priest song of all time, which barely beats out my favorite all time Metallica song, "Creeping Death")
1985: Anthrax - "The Enemy"
1986: Metallica - "Master of Puppets" (narrowly beating out "Fata Morgana" by Fates Warning)
1987: Helloween - "Halloween"
1988: Fates Warning - "The Ivory Gate of Dreams" (or, if you don't want to count that as a single song: Helloween - "Keeper of the Seven Keys")
1989: Fates Warning - "Part of the Machine"
1990: Judas Priest - "One Shot at Glory"
1991: Fates Warning - "The Eleventh Hour"
1992: Dream Theater - "Learning to Live"