Man, oh man. Darkest Hour was good. "Undoing Ruin" was the only one I got into, but I about wore the thing out.
Between the Buried and Me will be my generation's King Crimson. They are untouchable.
As far as prog goes, they will always be on a rotating list of bands. They're up there with Opeth and Agalloch for me, granted I don't know if Agalloch is considered prog or just black metal or whatever. Oh well. They genre blend in a unique way and I dig it. That's all that I care about. Haken is a prog band that caught my attention and kept it the past few years. I absolutely love "The Mountain."
You mentioned the dreaded "post-metal" label. I'd have to say I agree with your list. All of those bands are solid. I think Pelican is still relevant, but that kind of music is already such a niche crowd that I think it's hard to get new listeners. A lot of younger metal heads want Meshuggah or nothing now. Don't get me wrong. I like Meshuggah and "djent" (I hate that name) but I think people miss out on a lot of good music by shrugging bands like Isis, Red Sparrowes, etc. aside. Oh well.
Russian Circles, Pelican and Isis top my list for those kinds of bands. Neurosis is nuts too. I have a friend who is huge into Yob. I think I need to look more into them.
Anywho, rock on man. It's good to have people that can talk good music with these days.