First and foremost : Led Zeppelin
A close second: The Clarks
Anything with Eric Clapton in it
Dave Matthews
Hank Williams Jr.
Guns and Roses
Velvet Revolver
The Beatles
Jay-Z ( depending on the mood )
Distrubed
Staind
The Allman Brothers Band
Incubus
The Black Crows
....
the list could go on for a while ....
I'll listen to pretty much anything except most rap and country