Obsidian One
I remember reading a review in a magazine that said this album was so technical that people twenty years down the road would still be discussing it. Well, it's been almost twenty years, and Obscura is still one of the most complex, challenging, and difficult albums in my collection. I like to revisit it every now and then, and 'Nostalgia' remains my favorite track, though the opening riffs of tracks 1 and 7 are great as well. A classic death metal album that has been with me for years.
Favorite track: Nostalgia.