Optimus Prime by Adonihs on DeviantArt
What I love most about DeviantArt is the amount of quality work that is submitted everyday. Adonihs is an artist I've had in my bookmarks since I discovered his piece "The Journey Begins". He is a digital artist who works mainly in Photoshop and creates absolutely jaw droppingly beautiful digital paintings. I put a link up to his Optimus Prime piece because I also want to show you that he does mostly fanart that relates to what is popular today and because of that, he is also a bit of a DeviantArt celebrity.
I'm still learning the art of "painting" in Photoshop but my work doesn't come near the detail of Adonihs' digital paintings. His most detailed pieces resemble renderings from a 3D Program. He also has an advanced photoshop tutorial in his gallery detailing how he crated his King Kong piece.
I think that this caliber of digital art pushes the limit of what Photoshop can do. A similar effect can be achieved if you're also well versed in 3D programs, but for 2d "purists" in the area of digital art, Adonihs is definitely someone to emulate.