If you choose ePrompter's “Bounce” screensaver, it will
introduce a bouncing ball to a basically blank screensaver whenever an
email account gets at least one message. The bouncing balls will
reflect the chosen colors of the account, the number of messages, and
will change to reflect any change in the status of your new messages.
At any given point there could be as many as sixteen different colored
balls bouncing around the screen - but slowly enough that you can
still read how many messages you have.