I guess I'll get the ball rolling. There are so many illustrators out there that I like, it would be hard to narrow it down to one. But there is one who stands out. To me this guy is the painter's painter. His forest scenes that are used as backgrounds are mind-boggling to me. His name is Todd Harris. He works for Disney in the gaming business. This is his blog. No words, just pictures: http://hog-heaven.blogspot.com/ You'll find more work like his at his web ring: Avalanche Software: http://avalanchesoftware.blogspot.com/
I hope you're as inspired looking at his work as I am.