There's another way which doesn't use --no-desktop, I like it better since you don't have to mess with the Nautilus .desktop file and it's helpful in case you forget --no-desktop or if another program tries to open Nautilus...
You've noticed that if you kill Nautilus it just respawns and takes over the desktop again. In Xfce4 Settings Manager>>Session and Startup>>Session, set Nautilus>>Restart Style to "Never" and then kill Nautilus. While you're there, do the same to Thunar since you'll be using it infrequently and I haven't noticed any dramatic speed decrease from not having the daemon running.
Now run the following 2 commands in a terminal...
Code:
gconftool-2 -s -t bool /apps/nautilus/preferences/show_desktop false &
Code:
gconftool-2 -s -t bool /desktop/gnome/background/draw_background false &
You can now start Nautilus normally and it won't take over. Do so to get the daemon running and then log out and "Save session for future logins". Nautilus takes a second to open the first time you use it in a session, it's about as fast as Thunar after that.
You can undo the gconf commands by substituting the word false with true.
To change desktop wallpapers, either use Xfce4 Settings Manager>>Desktop or open Thunar, right-click an image and choose "Set as wallpaper".
Hope that helps.
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