I would suggest something the likes of "ubuntu-user" - perhaps a numerical count added if a similar one is found on the network (Do a quick search for anything named "ubuntu-user" then change to "ubuntu-user-0" "ubuntu-user-1" etc)
I would suggest something the likes of "ubuntu-user" - perhaps a numerical count added if a similar one is found on the network (Do a quick search for anything named "ubuntu-user" then change to "ubuntu-user-0" "ubuntu-user-1" etc)