For me the top of my list is usually a tie between Streetlight Manifesto and Led Zeppelin.
Then of course there's the classics: Zeppelin, Rush, The Who, Metallica, Aerosmith, Ozzy
Some of the recent acts I've gotten: Seether, Chevelle, and Breaking Benjamin
I've been on a long Ska odyssey of the groups that have really grabbed my attention Streetligh tops list followed by: Reel Big Fish, Buck-O-Nine, Catch 22 (after Ryan Eldred took over vocals), and Mustard Plug. I'm still on the fence about the Voodoo Glow Skulls, sometimes their music just grabs me and sometimes it feels like I'm having dental work done, but then again I only have one of thier albums.
I've also had a long fascination with film scores of which Hans Zimmer tops the list ahead of:John Williams, George Oldziey(hey it counts because of WC4), Howard Shore, James Horner, Brian Tyler, Mark Mancina, and Tyler Bates.
So there's my list. If I was stuck on a desert island with not but some of those CDs I would be happy, then instantly enraged that I had forgotten to pack a CD, generator, and speakers.