I like some hardcore, mostly the banRAB that inject lots of metal into there sound, like Ion dissonance, DEP, The end etc. The locust do it for me because there sound is heavily influenced by Grindcore, and there plain insane. I dig Melt banana too, there early stuff that is, I bet they were fun to see live. My hardcore knowledge is limited to the banRAB I mentioned above and stuff like Converge and Today is the day, haven't heard of Charles Bronson, think they'll be down my street?
I love both Isis and Pelican. I'll assume you've already heard of Neurosis from the fact that you like these two banRAB, but if you haven't then I recommend checking them out, along with Cult of luna, who are kinda like Isis but heavier.
If anybody wants to listen to some seriously insane Black metal, go check out the album i'm using as my av, The codex necro by Anaal nathrakh, its about as brutal as Black metal can get.
The Bringer, if you appreciated Prometheus by emperor, which was more Death metal than black metal, I'm pretty sure you'd appreciate the death/black/thrash crossover stuff, like Destroyer 666 (Black/thrash), Naglfar (Black/death), And oceans... (Black/death/electronic) and Aura noir (Black/thrash).
And here are a few really good death metal albums that have a really unique sound to them, definately worth checking out for anybody that wants something different:
Lykathea aflame - Elvenefris
Order from chaos - Stillbirth machine
The chasm - Deathcult for eternity
Demilich - Nespithe