Maybe I wasn't clear. You can switch back to the old notification system by installing the gnome-stracciatella-session package in Synaptic Package Manager, or by doing this in a terminal:
Then log off, and when the login screen comes up, press F10 to get the options menu. Choose 'Select Session' then choose 'Gnome (without Ubuntu specific components)'. It will ask whether to make the change permanent as you proceed to log in.
sudo apt-get install gnome-stracciatella-session
I recommend that you persevere with the new system - I didn't like it at first, but after tweaking the Update Manager notification and my Pidgin settings (that's where login notifications come from), I'm happy with it. Mackenzie's comments at http://ubuntulinuxtipstricks.blogspot.com/ are helpful for Update Manager.