There is a contest for Ubuntu 11.10 Oneric Ocelot wallpapers, have you submitted yet ? let's participate and do the best. For the best chosen picture will be available as default wallpapers in Ubuntu 11.10 and will shipped through the CD (ISO).

Please read carefully all requirement in wiki.ubuntu.com/Artwork/Documentation/Backgrounds.
 
Here are some Candidate of Ubuntu 11.10 Wallpapers from Flickr, submit your best picture and ubuntu will pick the best.
Ubuntu 11.10 Default Wallpapers Candidate

Submit your best wallpapers here (http://www.flickr.com/groups/oneiric-wallpaper-submissions/), it's can be photographic or illustrated image.