I like the new scripts. You're getting better and better! One thing though. You're so throrough that your script deletes itself, resulting in an error. It is of course a harmless error, but perhaps you should warn people. Perhaps just before the rm commands:
echo "You will now see an error, this error is because the script is deleting itself and is harmless."
(The error is: sudo: Unable to get working directory)

Other than that, it's great. This should definately be a sticky.