No Banshee notification area icon in Gnome 3 classic session

You can add the notification applet to the gnome-panel as shown in the picture.

To add, ALT+Win and right-click the gnome-panel to add the notification applet.

However, banshee is fully integrated in the sound-indicator, to perhaps the use of the notification icon is not required.

Install package: banshee-extension-appindicator

sudo apt-get install banshee-extension-appindicator

This package provides integration for Banshee with Application Indicators, which is a replacement for the notification area in Ubuntu, as a way to add menus in the panel.

REMEMBER to enable it as extension from banshee's preferences.