This is what I listen to:
Power:
Avantasia (opera metal supergroup)
Control Denied (with Death's members in it)
Dark Moor
Divinefire
Firewind
Iced Earth (with progressive, thrash, speed metal influences)
Lost Horizon
Myrath (power melodic progressive influences, VERY similar to Symphony X)
Outworld
Royal Hunt
Sonata Arctica
Symphony X (prog/power)
Progressive (favourite genre so far):
Ayreon
Circus Maximus
Devin Townsend/The DT Band
Dominici (ex-Dream Theater vocalist! his voice has changed quite abit too)
Dream Theater (!!!)
Fates Warning
Green Carnation
John Petrucci
Liquid Tension/Trio Experiment (basically Dream Theater without vocals/Trio = without Petrucci)
Opeth
Pain of Salvation
Porcupine Tree (I know not metal, but close enough Prog Rock, they just kick ass)
Riverside
Threshold
X Japan
Death:
Continuo Renacer (jazzy progressive death instrumentals)
Disarmonia Mundi (with Soilwork members IIRC)
Sculptured
Wintersun (progressive/melodic death influences, can't wait for their newest album "Time"!!)
Metalcore:
Darkest Hour
Heavy:
Dio
Iron Maiden
Thrash:
Metallica
Megadeth
Misc:
Ensiferum (good black metal)
Mammatus (excellent doom)
Electric Wizard (another good doom/stoner)
maudlin of the Well (avant-garde) now called: Kayo Dot
Subterranean Masquerade
Turisas
Yndi Halda (some good post-rock)
Muse (yeah!)
The Cure (really great rock)
Led Zeppelin (do I need to say more?)
An Endless Sporadic (unsigned Progressive/Rock/Metal band, featured on Guitar Heroes III)
*Bolded ones are the better bands I like =p
Basically I think metal is quality music. Not to put down other genres, but I just can't get of the "metal zone", it's like once you're in it you're addicted to it like drugs(in the good way)! Post more people, I hope my list helps you guys to expand your music horizons!