No power icon (unclear how to shutdown)

I have to agree here. I've had two non-techie family members use Ubuntu for a little while and both of them have asked how to turn it off - this should be more obvious than it is. One possible solution is to display "Session" instead of the user's name, then at least the menu's purpose makes sense just from looking at it. But then you have the problem that you don't know who is logged in. Perhaps the menu is trying to do too much? I would argue we need two menus the first has:

Username
  - Available
  - Away
  - Busy
  - Invisible
  - Offline
  - Guest session
  - Other user sessions
  - Lock screen
  - Log out

Then another one with just a power icon or something that has

 - Shutdown
 - Restart
 - Suspend
 - Hibernate

So the first has session related actions that don't affect other users. The second has power related actions that DO affect other users. Then the inclusion/removal of the second menu would change what appears under "System".

Kazade, the "shutdown" applet already does what you request (just not in a drop down menu) so in the meantime you can put that next to their usernames (I prefer the popup myself). I do agree, however, that the current indicator-session is not intuitive. It doesn't help that the shutdown commands are taken out the system menu if the session applet is running and so won't be in the natural place to look if you're coming from windows.

If an icon needs to be added there , then the new shutdown icon needs to be a greyscale one too.
Since the rest of the default panel uses greyscale icons...

Also > [speech bubble icon][username][power icon] would make the panel look a bit awkward.

IMO , It would be better cutting down one from the list to > [speech bubble icon][power icon]

Or simpler, if the indicator-session does *not* hide the shutdown/logout options from the system menu.

I think there may be an issue here in terms of implementing a greyscale power icon. Wouldn't this icon also be visible (and look out of place) in the dialogue you get when pressing Ctrl-Alt-Delete? Alternatively the icon could be hard-coded into the applet. This would look out of place in other icon themes, but would look right in the default set up at least.