If you like KDE and are using Kubuntu Lucid, you are missing out on the new wallpapers which have been chosen for Ubuntu Lucid after a photography contest. Unlike Ubuntu, these wallpapers are not installed on Kubuntu automatically. 
The wallpapers are great though. 
If you want to install them on Kubuntu, fire up Konsole and type the below command:
aptitude install ubuntu-wallpapers
Or if you prefer KPackageKit, then search for ubuntu-wallpapers package and install it.
You can then find the new wallpapers in /usr/share/backgrounds.
Not using Lucid or Linux but want the new wallpapers? You can download all the new Ubuntu Lucid wallpapers in compressed format from here.
Here is a teaser screenshot of my desktop with one of the new wallpapers. 
