First off let me state that Mikael is my favorite growler fro numerous reasons: his growl is distinct, he goes from deep to high, and there is so much emotion in a lot of his growling. Sometimes when he starts off growling with a closed mouth feel and then widens his mouth to that unleashed roar it gives me chills. I second the David Vincent suggestion. Not the deepest growler (and truthfully what he does a lot might not even be called growling). He does have distinction and he adds to the experience of the music, as opposed to many metal bands where it feels like the vocals sit on top of the mix. I like Barney from Napalm Death (Ripe for the Breaking, mmmm). Also, on the subject of metalcore/thrash bands like KsE, I love the dude from Unearth, as well as God Forbid.
Also, this might not exactly be growling as you would call it, but Johan Von Roy of Suicide Commando. It's terror EBM, not death metal, but I would highly suggest you guys check out the track 'Love Breeds Suicide', perhaps 'Raise Your God'. Love Breeds Suicide is one of my favorite songs ever, and on the album Mindstrip, which those tracks are off of, he had a wonderful vocal effect. Coincidentally, I have always wanted to hear Akerfeldt doing love breeds suicide.
Oh, Mr. Stanne also rocks my world. And does anyone hate me for actually liking John Tardy? (Obituary)