I have three artists I'd like to pimp: zo_cat, dark_velvet, and crystalkirk.
zo_cat, whose icons can be found at grarpirates, has some incredible stuff. His icons range from dark and moody to bright and crisp, and he always uses textures, brushes, and text impeccably. He also makes the most beautiful stock icons I've ever seen.
dark_velvet, who I discovered through grrliz, has very intricate and interesting icons. The colors are very clean, the designs are original, and the text is always very nicely done.
crystalkirk (who shares spookshowicons with detoxcocktails) is just... GUH. I love, love, love her coloring and her brush use. She can either make very "simple" icons or visually complex icons, but either works. I adore her use of space.
And now I'm just gushing.