Time for some honorable mentions:
1. Enslaved - Riitiir, Ruun
2. Isis - Oceanic
3. King Crimson - Lizard, Discipline
4. Fair to Midland - Fables from a Mayfly
5. Devin Townsend - Addicted!
6. Death - Symbolic, Human
7. The Mars Volta - Frances the Mute
8. Nightwish - Once, Century Child, Oceanborn
9. GYBE - Lift Your Skinny Fists Like Antennas to Heaven
10. Symphony X - Divine Wings of Tragedy, Paradise Lost
11. Coheed and Cambria - From Fear Through the Eyes of Madness
12. Dredg - El Cielo
13. Meshuggah - Obzen
14. Obscura - Omnivium
15. Riverside - Second Life Syndrome
16. Bjork - Vespertine
17. Depeche Mode - Ultra
18. Steve Roach - Structures From Silence
19. Robert Rich/Lustmord - Stalker
20. Queen - A Night at the Opera
21. Black Sabbath - Sabbath Bloody Sabbath, Master of Reality, self-titled
22. Epica - Design Your Universe
23. Ihsahn - After
24. Deftones - White Pony
25. Textures - Dualism
26. Witchcraft - Legend
27. Primordial - To the Nameless Dead
28. Quo Vadis - Defiant Imagination
29. Paysage d'Hiver - Winterkalte
30. High on Fire - De Vermis Mysteriis
31. Clutch - Blast Tyrant
32. Iron Maiden - Somewhere in Time, self-titled, AMOLAD
33. Radiohead - Hail to the Thief, Amnesiac, King of Limbs
34. Rush - A Farewell to Kings, Hemispheres, 2112
35. Pink Floyd - Wish You Were Here, Animals
36. Alice in Chains - Dirt
37. Katatonia - The Great Cold Distance
38. Deep Purple - Fireball, In Rock
39. Yes - Close to the Edge
40. Dream Theater - Awake, Train of Thought, Scenes
41. Iced Earth - Burnt Offerings
42. Alcest - Les Voyages de L'Ame
43. Wolves in the Throne Room - Two Hunters
44. Sigur Ros - (), Takk
45. Scar Symmetry - Pitch Black Progress
46. Iron and Wine - Our Endless Numbered Days
47. Jimi Hendrix - Electric Ladyland
48. U2 - Achtung Baby
49. Nine Inch Nails - The Downward Spiral
50. Nirvana - Nevermind
51. Metallica - And Justice for All
52. Protest the Hero - Fortress
53. Anathema - We're Here Because We're Here
54. Portishead - Portishead
55. Cynic - Focus
And of course:
56. Opeth - Still Life, Deliverance