Hmm... you have *tons* of choices when it comes to UNIX desktop

KDE
KDE is a powerful graphical desktop environment for Unix workstations.
http://www.kde.org/
=> EyeCandy for your KDE Desktop. Visual Enhancements for your KDE Desktop: Wallpapers, Icons, Themes. http://www.kde-look.org/

Gnome
Another user-friendly (powerful) desktop for Unix operating systems
http://www.gnome.org/
Gnome look, wallpapers and other sutff: http://www.gnome-look.org and http://www.gnome-look.org/

Above two or major desktops for UNIX and Linux systems