Better application defaults for the gnome sessions.

The gnome session and preferred applications are a bit short. It would be nice to have a panel in the preferences section where the *most common* session profiles could be activated. I talk about a dialog where the user could select to automatically start the mail notification, instant messenger, to-do list, media player. It would also regularly pol if the application is still running, eventually restarting it. Right now the users have to add them in the sessions dialog and it is not exactly new user's friendly. Also they have to install extra applications for applications like mail notification. A simple check-box model would enhance the user experience of normal desktop users.