Opeth was the first "growling" band I got into. Though I was pretty clear on that they were not really "death metal" from the start. I tried getting into Morbid Angel after I heard Mikael say they were a big inspiration. But I failed. I've tried a few times again with different albums, but they do very little for me. I can appreciate the musicianship and certain tracks (Maze of Torment!), but mostly it just goes in one ear and out the next.
The first Death Metal band I got into was Bloodbath, first through the Breeding Death EP and the first two albums. Loved the EP, didn't like the albums too much. Then came Unblessing the Purity and my fascination was renewed. After that I got into the albums too, in a big way. I'm loving The Fathomless Mastery right now.
I also went through Mike to Katatonia's Brave Murder Day/Sounds of Decay, onto the earlier stuff and other Death/Doom bands like Disembowelment.
After hearing Cynic I got into Death's Human album and pretty much most of anything Chuck ever did. While they were a part of the early DM scene they went way progressive towards the end, while still keeping some of the DM staples.
I also found Edge of Sanity through Mike's guesting on Crimson, and now I listen to most of their catalogue (at least anything involving Swano).
Then there are some other bands I like that don't really have any connection: Appalling Spawn/Lykathea Aflame, Entombed, early In Flames (back when Fridén still had a voice) + some other prog-metal (Isis etc) and a shit-load of Black Metal.
Whoa, indulging a bit too much there, methinks. Anyway to conclude:
If you're interested in broadening your tastes, I think you would do yourself a favour by A: looking into collaborations that Mike did with other bands (Katatonia, Edge of Sanity, Ihsahn etc), because odds are they're similar enough to be to your liking. B: get last.fm and browse the crap out of it. I've found tons of metal bands through there. The recomendations are far from accurate, but they at least give you direction and you get to sample most of everything.