Open a terminal and issue the command:
gconftool -s --type bool /apps/update-notifier/auto_launch false
This will do away with the Update manager automatically opening and revert to showing the update icon instead effectively reverting to original behaviour. The new method seems like a massive regression to me. I don't want to wait 7 days to have the computer randomly open the update manager, and even worse that 7days is reset if you used Synaptic, apt-get or add/remove!
I completely fail to understand why none critical updates should wait 7days before Ubuntu decides that you should install them, and reset the clock if you opened Synaptic in between.