Old school death metal with emphasis on chilling melodies. Added keyboards for extra atmosphere is very much welcomed. A few examples:

Dismember - Dismembered and In Death's Sleep (from the first album)
Desultory - Into Eternity (Forever Gone is the best example)
Death - Evil Dead (mostly the intro)
Merciless - Unbound
Unanimated - Ancient God Of Evil

Should give a good idea of what I mean. Doesn't have to be Swedish bands.

You may have heard it, but I think Necrophobic's The Nocturnal Silence is right up your alley.

Yes I have, and yes again, I love it.

Traumatic Voyage - Traumatic Voyage (this fits the bill just nicely.)
Nocturnus - The Key (You may know about them BUT if you do not know about them look them up.)

Runemagick's "Enter the Realm of Death" has a lot of cool melodies without losing any ballsiness.

Darkthrone - Soulside Journey. One of the best death metal albums I have heard and very chilling. This is before they went black metal.

Megaslaughter - Calls from the beyond

You may know them, but Crypt of Kerberos is a must. Think a Swedeath version of Nocturnus with some really off-the-wall touches and you'll have an idea. Keyboards check, chilling melodies check.

Here's the first track from their album:
http://www.youtube.com/watch?v=mMoDJxsEXJQ

Ok...


Carbonized - Avant-Garde Technical Death Metal. They later went in a more Grind direction.

Creepmime - I haven't really listened to them much. What I've heard is excellent old school Death Metal.

Deranged - Very early Swedish Brutal Death Metal. I think it was prior to the NY scene.

Excidium - Italian Death-Doom. They sort of have a taste for old horror films, great stuff.

Festerday - Pre-...And Oceans. Sort of like Nihilist.

Lemming Project - German Death Metal. Old school shit.

Leukemia - Early Death Metal with clean vocals. Also use lots of sound bites from movies and such.

Macrodex - Pre-C.o.K. Very raw, riff oriented Death Metal.

Morpheus - The Swedish one deserves much more attention than it gets, sort of like Wombbath.

Old Lady Drivers (O.L.D.) - Old-School Grind, with an avant-garde twist. Maybe what your after, but I'm not entirely shure.

Utumno - Progressive-ish Death Doom. Sort of like old Edge of Sanity and Sempiternal Deathreign.

Wombbath - No description needed. It's fucking Wombbath.


More later? That's enough for now.

Bloodstone (Swe) - Hour of the Gate, slightly thrash influenced, resembles of Necrophobic and Grotesque

Lost Soul (Pol) - Scream of the Mourning Star, maybe not exactly what you're looking for, fast and heavy with some twisted melodies accompanied with keyboards.

Morbius - The Shades Below, old school US style death metal, not crammed with melodies, but they are present. Somewhat like a doomier Nocturnus without keyboards

hmm

i'll say Immortalis, from Germany! they got weird melodic/keyboard parts thrown through some brutal, BRUTAL fucking riffs
http://www.youtube.com/watch?v=XOCdS_fqDP8
http://www.metal-archives.com/band.php?id=29093

maybe Phlebotomized from Netherlands, more brutal Cynic imo

Thanks to you all! There are a few bands here I haven't heard.

Abhorrence's Vulgar Necrolatry demo and Privilege of Evil from Amorphis should be exactly what you're looking for, if you're not already familiar with these releases.

I strongly second Crypt of Kerberos, although you ought to check out their Cyclone of Insanity EP before the full-length. The production is so much fucking heavier and the vocals are just massive. The album almost sounds watered-down in comparison.

Some other stuff:

Carnage - Dark Recollections (you probably know this one)
Interment - Where Death Will Increase
Macabre End - Consumed by Darkness
Crematory - The Exordium (the title track has the most chilling riff you'll ever hear)
Thou Shalt Suffer - Into the Woods of Belial
Nirvana 2002 - Promo 1991

Edit: A couple more that came to mind:

Hazael - Thor (Poland's answer to The Nocturnal Silence with some Unleashed thrown in)
Acid Death - Apathy Murders Hope