There seems to be a lot of confusion about the contours of heavy metal, the definition of "heavy" music, etc. The short answer is that Whitechapel's "A New Era of Corruption" is heavy metal and is heavy as f#^&. My longer answer follows.
Whitechapel's first album, "The Somatic Defilement", was top-shelf deathcore. With "A New Era of Corruption", they have melded their influences into a distinct, diamond-sharp alloy sheathed in state-of-the-art production. There are fewer breakdowns, but other facets of the music are highlighted-- particularly, the song-writing itself (not to encourage the idiotic cliché that song-writing and ample breakdowns are mutually exclusive). The vocals definitely are more up-front, as another reviewer noted, but Phil Bozeman is in the top echelon of metal frontmen. What the band did not do is crank out third-tier death metal.
A discussion of perception is appropriate to this review, as the lyrics to A New Era of Corruption read like a concept album examining themes of identity, perception, immortality, power, and technology. The album artwork is a perfect match, true to the urban, apocalyptic and sci-fi themes befitting deathcore.
I was looking at an Eyehategod review on here where someone mentioned the mind-expanding (herbal remedy -friendly) qualities of the record and I thought, yeah, I can believe it, it is abstract and heavy at the same time. Just because it is heavy metal does not mean it is not mind-expanding or even "psychedelic" in the narrower sense. Since the advent of the so-called grunge era at least, heavy music, including heavy metal, has consistently been the most psychedelic music available. Part of the reason should be obvious-- we, humankind are dense as bricks. Even the wisest members of our species will inevitably lapse into states of auto-pilot consciousness. In the face of this constant threat, we are best served by art that hits us with no less a degree of immediacy and finality than death itself. It drags us back into the moment. That is heavy-- the existential heaviness of Alice in Chains, Nirvana, Tool, Godflesh, Neurosis, and about a million doom metal bands.
Just as crucial to the psychedelic issue, though, is what the music looks like, and here I think "hard" is the right word. Taking the example of Eyehategod again, yeah they are heavy as hell, but I am not sure if you can call much of their music hard. Some of their riffs could break apart a glacier, but a lot of it is slow and plodding by definition. Nirvana, on the other hand, can be pretty propulsive and hard-edged-- look at Grohl's drumming for starters.
What you listen to should depend on the purpose to which you put the music. Do you listen to it to exorcise your demons? Do you listen to it to get motivated to hit the weights? To hit something else and let the music take you on a voyage? Do you listen to it to drink and be merry and sentimental?
I believe that heavy metal's true purpose is to paint patterns on the third eye. The incidence of synesthesia in the human population is probably higher than reported-- at any rate, it is very common for people to describe sound and music using visual metaphors-- "angular" riffs, or sound "colored" by the speakers. The great strength of metal is that it trims the excess sentimentality that clutters the pure music-listening experience, and focuses exclusively on the visual and visceral experience. When I listen to metal it has a shape, specifically because the sound is hard-edged.
Pantera, Slayer, Sepultura, Fear Factory, Slipknot, Lamb of God-- yeah, they are all heavy, but they are also hard as nails. If you want something of the same or even greater intensity, you need death metal or deathcore.
Whitechapel are gods of deathcore, but songs like "Unnerving" and "A Future Corrupt" will also satisfy your hunger for blastbeat-ignited death metal velocity. A few well-placed interludes (intros, outros)-- that evoke a subterranean graveyard for rusted borgs-- provide some well-needed breathing room.
Finally, there is something cathartic about a display of pure hatred in aural form, which is why hardcore punk music exists. If you are in the throes of righteous indignation, or lost in self self-pity, lovesick, or in a general rage because you have to get up and go to a braindead job, the grooves and hostility of the best songs on here, like "Murder Sermon" and "Reprogrammed to Hate", will get your head straight. But insofar as Whitechapel incorporate elements of hardcore savageness, it is more in the service of being "hard" than "heavy"-- that is, the bottom line is not the emotion it conveys, but the image it etches on your eyelids. That makes it heavy f'n metal.