I'm echoing the old and white comments...I too am a child of 80's music, and worked as a DJ for a while right out of high school (mobile; did mostly proms, grad nights and some private parties).
My tastes now run to more creative stuff, and there are a few I haven't seen mentioned, along with my personal favorites:
Rush
Dream Theater
Porcupine Tree
Muse
Cage the Elephant
30 Seconds to Mars
Shinedown
System of a Down
Nirvana
Pearl Jam
Soundgarden
Stone Temple Pilots
Amy Winehouse
Audioslave
the B-52s
Beastie Boys
Beck
CandleBox
Chris Weaver Band (new up and coming rock/blues group, saw them play a corporate event)
Daughtry
Death Cab for Cutie
Kings of Leon
Kid Rock
THe Killers
Rusted Root
Emeli Sande
OK Go
The Offspring
I currently have over 24K tracks in my iTunes library...and I'm just scratching the surface here!
Crap, forgot Oingo Boingo!