Just to throw my 27,000 Liras into the sub-genre discussion...
I understand why the classifying is necessary, although I don't like it. The real question is just how deep to we need to go?
Suffocation is death metal, we can call agree on that. But Cynic and Death also play death metal, albeit different shades of it. I don't think anyone would confuse those three bands. Someone who doesn't like Suffo might like Cynic(as, I feel, there is a large enough musical difference between the two to reasonably expect someone to like Cynic and not Suffo)--so lumping them all together simply as Death Metal is misleading.
So we call Suffo brutal death metal, or New York death metal, or whatever you like. And Cynic becomes Death Jazz or Death Fusion, again, what have you. But where does Death fit in? They're not brutal and not jazz, but they're kinda technical and progressive, so that's progressive death metal? Couldn't we just call Cynic progressive death metal then, and simplify things?
The devil's advocate in me says no, we can't do that, because Cynic and Death clearly sound different.
And the above worthless paragraphs are why I don't like the classification system. Differentiating between NWOBHM and black metal makes sense--there aren't enough shared characteristics to assume that fans of one genre would be fans of the other. But after a certain point, it really is just a bunch of rubbish...
I mean really, who only listens to melodic power thrash? So much so that when some technical power thrash comes their way they puke everywhere and van Gogh their ears to escape from the atrocity? No one? So we really don't need to have those sub-sub-sub genre classifications then, right?
Heathen says I should just listen to the music and bang my head. I'm inclined to agree.