I really like Converge and Gaza. Not really sure exactly how to explain what I'm looking for, but I guess I'm looking for intense guitarwork, polyrhythms, atmosphere, etc. For example, Jane Doe by Converge is a lot what I'm looking for. The intensity is over the top and songs on there are just pure chaos. A much less intense release (but still intense) would be No Absolutes in Human Suffering, Gaza's newest album. They focus a lot more on a sludgier approach with lush, atmospheric guitar textures, very reminiscent of atmosludge and Jesu. Starkweather would also fall in this category due to their proggy, doomy sound and their unique vocals.

I haven't heard enough of this stuff and I simply just can't get enough so any help at all would be appreciated.

Also, I wouldn't mind anybody throwing in some recommendations for bands like Integrity or Earth Crisis.

You may know at least some of these already:

Knut - Amazing swiss noise/sludge/core hybrid the Challenger album is incredible and very atmospheric.
Cult of Luna - Their first album is a harsh atmospheric sludge/metalcore, their later stuff is more post-rock stuff, second album is good too.
Coalesce - The Give them rope album is absolute chaos. I think Gaza took quite a bit of inspiration from them at least on their first album.
Botch - Interesting angular metalcore, everything they did was awesome We are the Romans is probably their best.
Kiss it Goodbye - Super pissed and dissonant metalcore.
Keelhaul - mostly instrumental, they move between sludge, metal, noise-rock their album II is my personal favorite.
Craw - Kind of like a more proggy Keelhaul but with vocals.
Cave in - Until your heart stops in particular, noisy metalcore with some spacier sections.
As the sun sets - Their first album was really caustic metalcore, from the 7744 cd onwards became schizophrenic noisy metalcore/grind they later became Daughters who are kind of similar.
Pageninetynine (pg99) - Noisy punk/hardcore stuff they get lumped in with screamo, check out the Document 5 and Document 8 albums the longer songs can be quite sludgy and sinister.
Pig Destroyer - Mostly grind but their stuff around Explosions in ward 6/38 counts of Battery is very dense and chaotic check out the song Pixie.
Drowningman - Kind of like a noisy metalcore/melodic hardcore hybrid, may not be exactly what you are after.
Creation is Crucifixion - Kind of tech-grind-metalcore hybrid, their records have some terrible production but the Child as Audience and the Re-recorded eps is probably their best stuff.

Maybe it's just because I'm listening to the album right now but Neurosis' Souls At Zero is the experimental hardcore/sludge/whatever album in my book. It's not fast or relentless as anything from Converge but there are many similarities with the post-hardcore paradigm of the nineties, only taken a step further. I don't know, maybe this recommendation is a bit of a stretch.

I think you might enjoy The Dillinger Escape Plan, The Tony Danza Tapdance Extravaganza, Botch, Car Bomb, Daughters, Narrows, Ed Gein, As the Sun Sets, etc.

I would recommend Zao for great metalcore with lots of different influences. Their discography is very diverse so if at first you dont like a song or album try another.

Pretty much everything everyone has said is great. Here are some more that I'm into:

Trap Them: Grimy as fuck metallic hardcore. Their newest record isn't as grind influenced as their old shit, but has tons of rad grooves
Nails: More on the grind side, but has a similar punishing atmosphere to Converge

I agree with this. Check out this song: http://www.youtube.com/watch?v=AYJcb5v54y8 (and of course watch it in HD, as the audio is better!)

Also check out Neurosis - Trough Silver In Blood

Everything I've heard here is great. I like a some of these bands (Nails, Neurosis, Coalesce) but I still have a lot to check out.

On a somewhat related note, I'm seeing Gaza tonight. Very excited!

Creation is Crucifixion

Have you tried listening to this norwegian band called 'Benea Reach'? They could up your alley.

http://www.metal-archives.com/bands/Benea_Reach/72293