James Paick is a freelance concept artist who has worked on more big games recently than I could fit in that headline.
Since I've got more room down here, here's a continued selection: The Last of Us, Uncharted 2, Prey 2, Infamous 2, Medal of Honor, Tomb Raider, Lost Planet 3...
...Resistance 3, Tron, City of Heroes, Rise of the Argonauts, Thor, Marvel Ultimate Alliance 2...OK, that should do. For now.
You can see a lot more of James' work at his personal site.
To see the larger pics in all their glory (or so you can save them as wallpaper), right-click on them below and select "open in new tab".