Rwarg... early.
Well, Jhonen Vasquez has probably been the biggest influence on my art. Before I started reading his stuff, I thought comic books were just about the goody goody super hero plots and whatnot. He inspired me to move into comic strips with my art, and possibly go for at least a minor in sequential art when I go to college.
Anno Hideaki - Not a conventional artist
per se, but Neon Genesis Evangelion really got me interested in religious symbolism.
Roman Dirge - Another comic book guy. Have you ever read "Where The Sidewalk Ends" or "A Light In The Attic?" His style is like that. I don't know why I bothered posting the link... the site is down.
I know there are so many more, but again, it's early. I'll post more when I remember them.
You might have more luck with the topic if you tried to get it moved to OT.