I struggle with this album. In a vacuum, it's a really good traditional metal album. There are a few annoying slow songs, but face it, most good metal albums have them. Also, as with many good albums that clock in over 60 minutes, the last few tracks start to blend together.
But these minor flaws are not what brings this album down. There is an intangible here, and it is not a good one. Since music and it's enjoyment involves emotions and mood, this intangible hurts this album's ranking.
This album suffers from it's legacy, and that is why so many metal fans of my era dislike it. This album seemed to cause a wave that killed metal temporarily. Just look at the 1990's and you'll see a dearth of good metal albums, and for some reason, this album serves as a signpost for that end. On the bright side, I believe it was this dearth that opened up so many of the great albums and bands from the late 1990's and early 2000's, but that doesn't absolve Metallica and this album of its sins.
As such, "The Black Album" lands at 499. As a side note, if not for Mariano Rivera, it may not have cracked the list.