Replacing gnome-screensaver with xscreensaver

[Johnny]

I'd like to replace gnome-screensaver with xscreensaver.  I'd tried:

    $ killall gnome-screensaver
    $ xscreensaver
    $ gnome-session-save

but alas, when I log out and back in I find that gnome-screensaver is
running and xscreensaver is not.  I'm looking for a more elegant
solution than deleting the gnome-screensaver executable and copying
xscreensaver in its place, although that solution is looking more and
more attractive.  Thanks.