Cam's stuff is pretty cool. He's got a lot of vatiety, too... you wouldn't have guessed the same artist drew some of that stuff.
Ever since the first "Alien" movie, I've loved H. R. Griger's work. His penmenship and attention to
every little detail is outstanding. I believe Xavier and a few others on here are pretty big Griger fans, too.
And of course Eva is just another mecha show. You can't go wrong with giant robots!
GIANT ROBOTS!!! 
EDIT: Oh yeah!
Winston Smith! I nearly forgot Winston Smith. He's a great collage artist, and has done album art for the likes of Green Day (Insomniac) and Dead Kennedys (Give Me Convenience, Or Give Me Death).