I seem to have a little bit of a different taste than most. Lately I have been hopping between the desktop wallpaper below and a solid black background. I feel that he solid black background makes it feel more like a literal desk top and that it is more productive, on the other hand, how can you pass-up Mario?
I use Debian Sid with KDE3 (although I have been playing with KDE4). I am running a AMD 64 X2 4200+ with a nVidia 7900GS, Sound Blaster Audigy 2 ZS Platinum Pro, 2GB of ram and a 10,000 RPM SATA 74GB HD in my compy. 74GB might seem a little tiny, but no worries. I have a 1.2TB file server with RAID 5 that all my desktops mount.
Some things that might need pointing out...
The only things on my system bar are the clock and the system icons (skype, pidgin, and amarok). I have removed the kde menu button because it can be accessed by Alt + F1. I have also removed the application tabs from the system bar. Open applications by be accessed by Alt + Tab or by middle clicking the desktop. I use yakuake for my terminal emulator. There is NOTHING on my desktop. I like to keep my files in folders and use the desktop for work space and not have it cluttered with random non-sense.
Enjoy!
P.S.
If you are looking from new/more wallpapers, PM me and I can send you a link to my person repo of wallpapers I have collected over the years.