Opinions

Amon Amarth
Anathema
...And Oceans
Arcturus
Bathory
Borknagar
Burzum
Celtic Frost
Darkthrone
Dan Swanö
Dissection
Enochian Crescent
Edge of Sanity
Emperor
Eucharist
Immortal
Katatonia
Mayhem
Mercyful Fate
My Dying Bride
Satyricon
Summoning
Ulver
 
I agree with a lot of Ormir's recommendations... certain discs that aren't there that I guess you'd wanna check out... given what you already have:

Alice In Chains - Dirt
Anacrusis - Screams & Whispers
Amorphis - Elegy
Arch Enemy - Black Earth / Stigmata
Arcturus - The Sham Mirrors
At The Gates - With Fear I Kiss
Babylon Whores - King Fear
Blind Guardian - Imaginations From The Other Side
Cemetary - Sundown
Dimension Zero - Penetrations From the Lost World EP
The Haunted - S/T
Iced Earth - Something Wicked / Burnt Offerings
Iron Maiden - Number of the Beast
Lake of Tears - A Crimson Cosmos / Forever Autumn
Nevermore - Dreaming Neon Black
Paradise Lost - Draconian Times / Icon
Rainbow - Long Live Rock'n'Roll
Raunchy - Velvet Noise
Sentenced - Amok + Love & Death
Therion - Theli / Vovin
Throes of Dawn - Binding of the Spirit
 
Thanks for the recommendations so far. I have been wanting to get some older Arch Enemy, and the few songs I have heard from ...And Oceans have interested me as well. Also I have had some friends tell me that Sentenced Amok is a must have. I plan on purchasing a few dozen more albums so keep the recommendations coming as I will be making a list soon.
 
To be more specific:

Amon Amarth
-Once Sent From The Golden Hall
-The Avenger
Anathema
-Judgement
-Alternate 4
...And Oceans
-Cypher
-AMGOD
Arcturus
-La Masquerade Infernale
-Aspera Hiems Symfonia
Bathory
-Twilight of the Gods
-Blood Fire Death
Borknagar
-s/t
-Archaic Course
Burzum
-Aske
-Hvis Lyset Tar Oss
Celtic Frost
-To Mega Therion
-Into the Pandemonium
Darkthrone
-Transilvanian Hunger
-A Blaze in the Northern Sky
Dan Swanö
-Moontower
Dissection
-The Somberlain
-Storm of the Light's Bane
Enochian Crescent
-Omega Telocvovim
-Telocvovim
Edge of Sanity
-Crimson
-Purgatory Aftergrlow
Emperor
-In the Nightside Eclipse
-Anthems to the Welkin at Dusk
Eucharist
-Mirrorworlds
Immortal
-Pure Holocaust
-Battles in the North
Katatonia
-Brave Murder Day
-Discouraged Ones
Mayhem
-Mysteriis dom Sathanas
Mercyful Fate
-Don't Break the Oath
-Melissa
My Dying Bride
-The Dreadful Hours
-Turn Loose The Swans
Satyricon
-Dark Medieval Times
-The Shadowthrone
Summoning
-Minas Morgul
-Stronghold
Ulver
-Bergtatt
-Nattens Madrigal
 
Thanks for the recommendations. I am looking into mail ordering several cds now.
Anyone wanting to hear some new music can go to my site and follow the link for Somnus. They are a local Doom/Black Metal act and they are very cool. They played the Milwakee Metalfest several years in a row. I think you will like them.
 
Dimmu Borgir - Enthrone Darkness Triumphant
Detonation - An Epic Defiance
Enter Chaos - Dreamworker
In Flames - Lunar Strain
In Flames - Subterranean
Nevermore - Dead Heart In A Dead World
November's Doom - To Welcome the Fade
 
I have the Nevermore album. I have seen Dimmu and Immortal both live so I should certainly get them. Also the 2 first In Flames I know I need. I ordered some Summoning based on recommendations too.

Yes, Somnus is on Root of All Evil. Awakening the Crown is very cool, and the new one I have seen them do live a few times, but do not own the album, just the 2 mp3's on their site.
 
HI!
I think you should get also:

Death - The sound of Perseverance
Judas Priest - Painkiller
Queensryche - Operation Mindcrime
The Gathering - Always / Mandylion / Nighttime Birds
Within Temptation - Enter / The Dance