The Japanese illustrator Tomomi Kobayashi has been one of my earliest and most consistent inspirations. She is, first and foremost, a watercolorist, and is most known this side of the ocean for her work on Square's experimental SaGa series and the MMO Granado Espada. There is an obvious elegance to her work - in her lines, her use of color, her stylistic approach to rendering characters, her combination of organic nouveau and geometric deco elements to create a style that encompasses both the romantic and heroic traditions (incidentally, perfect for the type of video games that she has worked on).
My favorite Tomomi Kobayashi pieces are those done for SaGa Frontier on the original Playstation, probably due to the sheer variety in types of characters she had to tackle. This piece is fairly representative of that body of work. I especially like the approach she has taken to the designs of the characters. There is a good balance of form and function here - these designs actually make sense and don't feel like they have been created only to look cool, yet they are beautiful nonetheless.
If anyone is interested in watercolor illustration, it's definitely worth it to check out her work. She has a site at http://www.kobayashi-tomomi.com/. It's in Japanese, but the art is not hard to find. (However, the majority of her SaGa Frontier work is not up there. You'd have to Google that.)