Yuko Shimizu recently posted a gallery of amazing science fiction-style art at the portfolio site Behance. A couple were covers for the Vertigo series The Unwritten, but most consisted of book covers and illustrations that were too good not to share. Shimizu posts pictures of the unadorned illustrations beside shots of the images out in the wild, for context. As well as being a great illustrator, she's an extremely talented designer.
My personal favorite after the jump may well be the Robert Crumb-referencing piece for a Fused TV magazine ad: Keep on space truckin', indeed.