First of all (some may disagree), System of a Down, Korn, Metallica after ...And Justice for All =/= metal!
That's not a snobbish, ignorant comment on my part, but a reflection of attitudes amongst traditionalists in the genre. There is a major rejection of most everything American in the metal genre these days, which is sad given there are a lot of good bands from the states. To get respect and notoriety they tend to sound like they are from Sweden.
Where is metal today? Well like most everything else metal is EVERYWHERE!
The gravitational center of the metal sound, though, is Scandanavia, and particularly Norway and Sweden. Some great bands from Finland, too. You can get into Black Metal vs Death Metal, but really there is European metal and there is American metal. America dominated metal in the late 80's, early 90's with releases like Slayer's "Seasons in the Abyss," and Morbid Angel's "Covenant," but that is more or less "the past" in the world of metal. It's inspirational to what's happening now, but production wise there isn't much of a similarity.
Much more important I would say would be bands like Dark Funeral, Amon Amarth, Bork Nagar, Hypocrisy, Behemoth and Dark Fortress. Those are some of my favorites anyway. I really dig Vintersorg, too, but he stands alone! I don't think I'd really even compare anything else to it - the guy sings about particles. Lol.
If you have a metal band you have to figure out which genre they fit into best, and I like to think about it more regionally and by time period: Norwegian Black Metal circa 1991 does NOT sound like Scandanavian extreme metal music of 2012. There is a vast difference, and we're talking about the same place, even the same general musical style. Vastly different production esthetic.
There's classic metal:
Black Sabbath
Motorhead
Led Zeppelin
Deep Purple
New Wave (British) metal:
Iron Maiden
UFO
Thrash:
Anthrax
Slayer
Metallica (pre-Black)
Megadeth
Testament
Death metal:
Cannibal Corpse
Deicide
Sepultura
Morbid Angel
Each has its own esthetic, and trust me people get VIOLENT about some of these subtle differences sometimes. It's almost ridiculous. It does pay to be aware of where you band stands in this whole mess, though, because you may want to come at it with a muddier sound. Or you may want more compression and definition. Metal is very hard to generalize, but I wouldn't say Metallica is even in the same galaxy as what would be considered metal today.
As for drums I'd say that is the foundation of your sound. I have discovered through writing and recording metal that I will often mix it more like Hip-Hop, starting out with the kick, snare and vocal and then bringing in the bass, and finally guitar making sure the vocal and snare are still defined, and not crowded out by the guitar. The more I get into the low-growl death metal sort of esthetic the more I feel it is really a drum-and-vox type of thing. Guitar is almost a carnival side show to the brutality happening in center stage.