used to listen to a lot of metal, but in recent years i've sort of gravitated toward indie rock and post-punk... feel like i can still contribute to this thread, i guess.
for anyone interested in funeral doom, i'd recommend that you listen to esoteric's the maniacal vale if you haven't already. it's a really long listen (over one hundred minutes!), but it's really worth it. the songs on the album are relentless and assiduous, sometimes stretching to over twenty minutes in length, but there are very few dull moments on the record. the ambient sections are also really great. iirc metamorphogenesis is a bit more ambient and drony, but that's part of the fun of listening to it.
uhh, other stuff that i can recommend from the top of my head would be antediluvian's through the cervix of hawaah (death metal), the ocean's precambrian (prog?), and electric wizard's dopethrone. feedbacker by boris is also worth a mention if you like sludgy/drony stuff i guess.
other things:
salvation by cult of luna
through silver and blood by neurosis
christmas by old man gloom
jesu by jesu
si monumentum requires, circumspice by deathspell omega
obscura by gorguts (I think BKC mentioned this; I found this record when I was in middle school, and it's still probably the best death metal album that I've listened to; although I haven't listened to anything comparable to it, I'd recommend Nesphite by Demilich if you haven't already checked it out)
above the weeping world by insomnium
first four are sludge, dso is black/death i think, gorguts is death metal, insomnium is melodeath
sorry for the long post. i know very little about metal, so i apologize if my recommendations are things you've already heard!