I just listened to one of their songs on Youtube and the vocals were really good. Give the band Rottrevore a listen, I think you might like them.
hmm they have some slow songs which is kinda doom/sludge ish. I like a lot. So far I've only listened to Incompetent Secondary and it's nice and heavy.
Groove metal is not a genre, it's a "title" given to any band that has a groovy sound regardless of the genre they would be. Pantera were groove and they were a post-thrash band; Pig Destroyer are groove on one album and they're a grindcore band.
Back to topic: I like Cannibal Corpse, Six Feet Under, Obituary, Death, Dying Fetus and Paths of Possession (who are actually a melodeath band). There may be more.
Actually they consider groove metal as a part of post thrash metal. I have never heard of pig destroyer being called groove how do you come to this conclusion? They may be inspired by slayer and shit but I wouldn't call them groove.
I was just listening to some Septic Flesh. Fantastic band Other favourite DM bands: Gojira, though they are also pretty thrashy and progressive. Behemoth (later albums like Zos Kia Cultus onwards are almost completely devoid of black metal elements) Cynic Opeth Bloodbath Unleashed
Opeth is the only death metal band I like- Watershed is a pretty good album, and the way their vocalist transitions between growling and lcean vocals is pretty interesting.
Looking at Cannibal Corpse's song names, well to be frank it puts me off. Relatively...violent and sexually oriented. Not my type. Metal yes. But not death metal. Sorry. =p