Ok, I've checked out some of this stuff (some I had already checked out and just wanted some opinions), and here's my take on them:
Aeternus - I checked out "Beyond the Wandering Moon" and "Shadows of Old". Moon is pretty good, unique black/death with an almost doom atmosphere, where Shadows just seems like basic death metal. Not bad, nothing special. But Moon is good!
Bestial Warlust - I checked out "Blood and Valour", which is noisy, but pretty bland black metal. I could see myself listening to it once in a while, but not really enjoying it.
Abhorrence - "Envoking the Abomination" is pretty standard, boring Brazilian death metal. It just sounds like a lesser version of Krisiun with a bad drummer to me, sorry.
Anorexia Nervosa - "Drudenhaus" sounds a LOT like early Cradle of Filth. It's BETTER than Cradle though, but still, not great. It's intense though.
Arkona - I'm not a big fan of blast blast blast black metal, but this is pretty decent. I've only heard "Nocturnal Arkonian Hordes" so maybe they have better albums. I don't like the guys voice though. It's decent.
Belphegor - I find it weird that you said that Belphegor is standard death metal and said that you like Abhorrence. This is pretty good blackened death, while not exactly unique, it's much more so than Abhorrence (not trying to start a fight though). This reminds me of a much more black metal version of Behemoth.
Ad Hominem - Straightforward but good NS black metal. I see what you mean about it not being essential but being good.
Arckanum - I like "Kampen" quite a bit. It's not entirely unique but it has some pretty interesting moments. Not brilliant but good.
Armagedda - Definite Darkthrone worship. Not horrible but generic.
Averse Sefira - Wow, this definitely stands with the best of USBM. Pretty unique and interesting stuff.
Axis of Advance - Decent, but something about it reminds me too much of Mayhem's "GDOW".
Azaghel - Not bad, but generic. Some cool melodies.
Countess - Pretty cool, not the greatest thing I've ever heard, but good.
Behexen - Blast blast blast black metal. Not my thing, but not bad for what it is.
Bloodthorn - Decent. Somewhat cool atmosphere. No real identity of it's own though.
Cephalectomy - This is one of the bands that I've already heard. I love this band, I just think they're highly under-rated and wonder what other people think of them.
Here's a couple more bands:
Cult of Daath
Daath
Disavowed
Empyrium
Fleurety
Gontyna Kry
I Shalt Become
Kekal (I've heard them, but curious to see other opinions)
Kronos
Massacra
Megiddo
Mithras
Nachtfalke
Nagelfar
Obtained Enslavement
Psypheria
Rehtaf Ruo
Sacramentum
Summon
Theory in Practice
Thunderbolt
Vinterriket
Watain
Weakling
Windham Hell
Wormed
Xasthur