Sam Bosma is bloody marvelous. I love everything about his work at the moment. He's got such a knack for full environments and scenes, the detail is immense. He works digitally, which isn't usually something I'm all that into, but he manages to pull it off so well and give it a really organic, natural finish. His recent Hobbit stuff for the Picture Book Report is really excellent. Look out for the posts about his process, they're fascinating.