I would have thought mine was such a common question that there would be a simple solution already built in to xubuntu - but there isn't.
I have 2 separate external hard disks and connect them to a USB port at different times - I would like them to be automatically mounted as read/write, but apparently the designers of gnome-volume-manager decided that shouldn't be possible and they are mounted as read-only.
In fact, I can write new files to them, but cannot then delete the new files I just wrote!
Is there a workaround? I read somewhere that etc/fstab doesn't apply to removable media, which are mounted by gnome-volume-manager and therefore cannot be unmounted by a user.