"Screensaver Settings: Configure the settings of your Gnome screensavers."

Screensaver Settings provides an almost identical interface to that provided by gnome-screensaver-preferences but with the addition of a "Preferences" button that will let you change the settings of any of the screensavers in your system.

Additionaly, you will also be able to select which set of screensavers should be used while in "random" mode.

gnome screensaver, xscreensaver, screensaver settings