714 wonderful backgrounds!
Yes, in my personal opinion, bing.com is only useful in supplying fresh backgrounds, which are breath taking. These breath taking set of wallpapers, when set to change randomly on your desktop, makes the look and feel more exquisite.
Download the file(see below). The script and the images are inside the tar file. Untar them in your home directory, chmod +x bing_change_wallpaper.sh and place the file in /home/user/bin/ directory. Rename the images folder to .bing_wallpapers and place it in your home. The script by default changes the wallpaper every thirty minutes, you can edit the script to your satisfaction. For GNOME only, click on System -> Preferences -> Startup Applications, with the following entries.
Name: bing backgrounds switcher Command: /home/user/bin/bing_change_wallpaper.sh Comment: bing backgrounds switcher