Larry Elmore's use of background is vastly unappriciated.
I like individual WAR paintings, but not overrall. Every one is the same thing: someone kicking butt. That's it. The Satyr in the 3.5 Monster Manual was especially disapointing in that regard. He's a decent enough artist I just wish he had a greater range of style.
For "comic art" I prefer the retired David Trampier. It is a true shame he stopped painting.
But I guess my faves are DiTerlizzi and Brom. Both of those guys really know how to evoke mood.
Just my two cents.