Do you like to get a little notification for new mail? If you use Apple Mail then you can find a number of different plugins to notify you in many ways. MailFX will display a graphical animation.
The plugin is easy to install and remove (it comes with an uninstaller) and can be activated from Mail>Preferences>Rules. We did have some trouble launching it though and had to run commands in the Terminal to get it working.
MailFX offers only five different animations and you will not be able to add your own or decide where it shows up on the screen (bottom right). However you can adjust the display time and visibility of the graphic and choose from more than a dozen sound alerts to associate to the plugin.
Despite offering a limited number of animations and some trouble with installation, MailFX may well suit Apple Mail users looking for graphical notifications. For a sleeker notifier I would suggest Mail.appetizer.