I came across the illustrations of David Downton a few year ago, flipping through some article on fashion illustration. He does these phenomenal illustrations and celebrity portraits. Downton's signature is his use of negative space. By leaving out a detail, he brings out the greatest details of his piece. He will actually go back to a near-finished piece and start taking away until it's just right. He uses watercolor and gouache on small pieces, india ink on line drawings, and his larger pieces are cut paper collage and acetate. I love this man.
If you love what you see, too, check out the prints for sale at the Fashion Illustration Gallery.