I upgraded a desktop machine from Debian Squeeze to Debian Wheezy. After the upgrade, the power button was mapped to a suspend action, instead of a shutdown as in Debian Squeeze.
In order to map the power button to a shutdown action, I had to do the following;
'nothing' by means of dconf (for all users)
2) Add a new section
[org.gnome.settings-daemon.plugins.power] with the line