One of my favorite artists/illustrators is Wayne Reynolds. He has been doing a lot of work for Wizards of the Coast and Paizo Publishing, including the main art for Eberron and Pathfinder. Have a link to a bio, a bibliography, and two small galleries (the first is larger), along with wallpapers and larger images. You can also find his stuff scattered throughout the Wizards of the Coast galleries, not always listed by name. I can’t find a good single place for his stuff, and not all of it is online (like some nice ones from Dragon that made it into the Compendium book, which does not have a gallery that I could find).
Flipping through the Wizards archives reminds me that Sam Wood has also done a lot of great art for this generation of Dungeons and Dragons. If you have a favorite piece from D&D 3rd Edition, it is probably from one of those two or Todd Lockwood. Anyone know of any games that are tapping these folks?