To change applications settings, most notably where Rhytmbox keeps its music folders:
$ gconf-editor &
This opens a GUI editor.
To update where the screensavers picks it pictures from (XDK_PICTURES_DIR):
$ gedit .config/user-dirs.dirs
The current contents are:
XDG_DESKTOP_DIR="$HOME/Desktop" XDG_DOWNLOAD_DIR="$HOME/Downloads" XDG_TEMPLATES_DIR="$HOME/Templates" XDG_PUBLICSHARE_DIR="$HOME/Public" XDG_DOCUMENTS_DIR="$HOME/Documents" XDG_MUSIC_DIR="/mnt/shared/music" XDG_PICTURES_DIR="/mnt/shared/photos" XDG_VIDEOS_DIR="/media/multimedia/videos"
Use dconf-editor
(this needs to be installed, if not available) and navigate to:
org.gnome.desktop.media-handling
to enable/disable auto-mount of media folders (eg, connected USB disks, loop devices)