Presumingly somewhere hidden between gnome-session-properties, gnome-tweak-tool and dconf-editor, but that’s the easierst way:
$ vim ~/.config/user-dirs.dirs XDG_DESKTOP_DIR="$HOME/Desktop" XDG_DOWNLOAD_DIR="$HOME/" XDG_TEMPLATES_DIR="$HOME/" XDG_PUBLICSHARE_DIR="$HOME/" XDG_DOCUMENTS_DIR="$HOME/" XDG_MUSIC_DIR="$HOME/" XDG_PICTURES_DIR="$HOME/" XDG_VIDEOS_DIR="$HOME/"
Mainly for the reason that upgrades might re-create the nastly default dirs.