Notification to the user when kernel detects a USB connect / disconnect

A notification should be sent to the user when (s)he connects or disconnects an USB device. May it be a sound or a notification-balloon -popup. Most of the users may think that the device (s)he connected is not working in ubuntu or something similiar if (s)he does not receive a notification of a connected USB device. (Like myself during the first days of "from windows to ubuntu")

See also this specification:
https://blueprints.launchpad.net/ubuntu/+spec/new-hardware-plug-in-notification