Sam Brown is another of the talented kids at concept art studio Massive Black. His work has appeared in games like BioShock 2 and inFamous.
Love his robots. They always look their best when they're functional, dirty and a little banged up.
You can see more of Sam's 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".