My wallpaper is currently a couple of Bill Watterson watercolours on a 30 min rotation. The t-rex in an F14 and a Spaceman Spiff spacescape.
You will all note that my desktop is very sparse. I reserve it as a workspace rather than a launcher. A much more logical use of the space in my opinion. All the items currently located on my desktop are things I am either reading, using or are folders that contain projects and resources related to uni.
Conversely my Start screen is well structured in a personalised way for easy access to all the applications, directories and tools I might care to use or open while making use of the larger yet more efficient space provided. You know, the way it was intended. Everything is better for it.
EDIT: Links for the wallpapers if anyone wants them
T-rex in an F14 (1920x1080) [https://dl.dropboxusercontent.com/u/78550908/dinosaur_cartoon-wallpaper-1920x1080.jpg]
Spaceman Spiff spacescape (1920x1200) [https://dl.dropboxusercontent.com/u/78550908/xspiffinspace1920x1200.jpg]