Black Sabbath - Paranoid
Metallica - Master of Puppets
Linkin Park - Hybrid Theory
unsure for a 4th.
but Linkin Park honestly deserves a spot there because it ended up being the album of a generation and a half, as well as a massive transition of metal with subgenres coming out of it.
"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.