I've never really been a fan of USBM, so bare in mind most of the bands I rec will probably be fairly untypical of the "scene"
I have a few Krieg stuff (mainly splits), Not that impressed with them really.
Judas Iscariot is far and away the best BM band America ever produced (even if he did relocate to germany for he's last couple of Albums). All he's albums are good, start with "Thy Dying Light" and "Heaven in Flames", that will give you an idea of he's older vs newer style albums.
I always thought Xasthur were pretty overated, I've only heard "Nocturnal Poisoning" but was really not that impressed. If you want some good suicidal bm, check out Leviathan instead, I've been getting into them pretty recently.
Vrolok is another really good USBM band, I have both their "Resurgence" albums though I'd say Resurgence: II, is my favorite, their sound is kind of hard to describe, on their first album it's pretty fast and all out agressive, whilst on part II it's more droning and drawn out, something I prefer, the albums are part of a trillogy (kind of like what Kanwulf did with Rasluka) so it'll be interesting to see what Resurgence III sounds like (due out later this year I think)... Anyway here's a link to one of their songs
http://download.yousendit.com/1095E4571B55432D check it out if you want.
Also because it's almost obligatory, Velvet Cacoon, everyones favorite inside joke...