Metalcore is strongly disliked because it blends elements of metal with hardcore punk into a formula that a lot of people find really bad. Also, because it frequently takes themes from punk and metal (antisocial stuff, anger, disenfranchisment) and makes them stupid, i.e. that Chimaira song that goes "I HATE EVERYONE"
Now, I happen to have seen Chimaira live, and they totally kicked ass, but most people on here will give you shit for listening to metalcore. My guess, though, is that once you listen to a lot of "true" metal, you'll probably stop listening to metalcore so much.
For now, some stuff that's not too far off from metalcore:
Soilwork - Stabbing The Drama
Pantera - Cowboys From Hell, Vulgar Display of Power, Reinventing the Steel
The Black Dahlia Murder - Unhallowed
In Flames - Soundtrack To Your Escape (Metalheads generally dislike it, but metalcore fans tend to dig it, and I think it's a solid album)
At The Gates - Slaughter Of The Soul
And check out Hatebreed
And then a couple that are basically required listening:
At The Gates - With Fear I Kiss The Burning Darkness
Emperor - In The Nightside Eclipse
Iron Maiden - Everything, but specifically Iron Maiden, Killers, The Number Of The Beast, Peace Of Mind, Powerslave, Somewhere In Time, Seventh Son Of A Seventh Son, Brave New World
Motorhead - Ace Of Spades, Bomber, Overkill, Orgasmatron
Judas Priest - Sad Wings Of Destiny, Screaming For Vengeance, British Steel
and I'm missing a whole bunch or whatever...too bored of the "essentials" list to finish it. Enough there to get you started.
I agree with the Hypocrisy recommendation. good gateway album. "Abducted" is good too.
what you said you already like is generally referred to as "metalcore" (and not fondly at all) and is rather similar to melodic death metal (which Hypocrisy is)
I'd also suggest these:
Ensiferum - Ensiferum
Mithotyn - Gathered Around the Oaken Table
Amon Amarth - Versus the World
Amorphis - Tales From the Thousand Lakes
Dark Tranquillity - Damage Done
In Flames - Lunar Strain
In Flames - The Jester Race
Insomnium - Since the Day It All Came Down
I second these.
Odyssey is great, especially the song.
I dunno, I felt that the only thing on there that stood out was Inferno. The Odyssey was pretty cool too.