I like just about anything thats hard or heavy...alot of instrumental stuff.

KoRn
Marilyn Manson
Slipknot
MegaDeath
System Of A Down
Mudvayne
Adema
Rage Against the Machine
Clown
Tool
Dope
Rob Zombie
KISS
Kid Rock (only a little bit)
Lit
Metallica
Nirvana
P.O.D.
Creed
The Offspring
Red Hot Chili Peppers

On the other hand I like to keep things varied, so I like a few soft (not too soft now ) songs on my playlist.

3 Doors Down
Sum41
Blink 182
Muse
Coldplay
Def Leppard
Dave Matthews Band
Bloodhound Gang
Dynamite Hack
Gorillaz
Drop Kick Murpheys
No Doubt
Rehab
Train
U2

I have a couple more...I just have a really bad migrane now