I'm sorry, I thought you were going to name metal bands. Soilwork is alright, and God Forbid ain't bad. LoG, Pantera, Sepultura, and Soulfly are also good choices. The rest, not so much.

If you want to get into metal, you should try to figure out what it is, in particular, that attracts you to it, and go from there. Machinae Supremacy is a good way to cut your teeth. I would also reccomend checking out Apocalyptica, particularly their non-cover stuff; they're an amazing band.

Follow Scott's advice and find what you like in the old stuff; you should be listening to those classic awesome bands anyway. From there, you can branch out and find bands that go in new directions. A few of the bands I listen to:

Progenitor Extreme Metal Bands
Death
Mayhem
Burzum
Mercyful Fate
Venom
Celtic Frost
-this stuff is from the early/mid-80's and is the origin of modern black and death metal, and associated sub-genres

Death Metal/Progressive Death Metal/Melodic Death Metal/Blackened Death Metal/Melodic Progressive Blackened Deathgrindcore
Cannibal Corpse
Nile
Deicide
Bolt Thrower
Gojira
Decapitated
Cattle Decapitation
Necrophagist
Amon Amarth (more melo-death/Viking death)
Children of Bodom (progressive melo-death)
Behemoth (also had a black/death phase, and started off as black metal)
Arsis
The Faceless
Arch Enemy
Therion (first two albums)
In Flames
Dethklok
Goatwhore
Vader
Skinless
Lamb of God
Shadows Fall (progressive death metal)
Mastodon (sludge metal)
Dark Tranquility

Classic Thrash
old Metallica
old Megadeth
SLAYER!
Anthrax
-These are The Big Four of 80's metal; if you like metal, listen to these guys. If you really like Slayer, you may be ready to dip into the more extreme stuff (like the death metal)

Progressive Metal/Power Metal/Symphonic Power Metal/Symphonic Metal
Jag Panzer
Kiuas
Blind Guardian
Hammerfall
Gamma Ray
Helloween
Kamelot
Rhapsody (of Fire)
Conception
Dream Theater
Symphony X
Dragonforce
Stratovarius
Savatage (really more progressive rock, but fuck you, I like 'em)
Nevermore
Iced Earth
Therion (after their first two albums)
Nightwish (with Tarja)
Epica
Manowar (more classic metal, but you should really listen to them)
Opeth
Pain of Salvation (metal-ish, more prog than anything else)

Black Metal/Gothic Metal/Doom Metal
Dimmu Borgir
Satyricon
Cradle of Filth
old Behemoth (as mentioned above)
Einherjer (Viking Black metal)
Type O Negative
Lacuna Coil
The Sword (very Black Sabbath-esque; a good place to get started)

The Odd Ones
Strapping Young Lad (and other Devin Townsend projects) - makes music that is difficult to classify; mostly industrial/death/thrash/progressive
Finntroll - folk metal, with a black metal streak
Korpiklaani - straight out folk metal
Buckethead - not strictly speaking a metal guy necessarily, but you should check him out
Fantomas - I put this here because Rym and Scott hate them fiercely; weird experimental death metal fronted by Mike Patton - it's interesting, but I don't know if I like it or not


I'll edit in more as I remember them, but this is a good start. If you could post what metal bands you've heard so far, that'd be a great help. You can find videos of a lot of these folks on teh Youtubes.