One of my all-time favorite artists, Bryan Tyler, is on quite a roll recently with his eye-popping posters for Ridley Scott's Alien and Blade Runner. Loving the technique; I'm so used to his clean lines I honestly didn't know it was him. Check them out here and here, respectively.
If you're not familiar with his work, you should be. Check out Bryan's carnival of awesome here. And hell, since I'm throwing out pub links all over the place, buy his Kickstarter-funded book here.