I know that there were some issues with keyboard shortcuts and with suspending (without password) in 12.04. The shortcut problem is fixed in 12.10. I defined a custom shortcut Suspend (Super+S) via
(dbus-send --system --print-reply --dest="org.freedesktop.UPower" /org/freedesktop/UPower org.freedesktop.UPower.Suspend). This command I used for suspending under 12.04. It also works from the terminal under 12.10, however, it doesn't suspend (why?) when defined as a custom keyboard shortcut.
What's the best (under 12.10) way to define a keyboard shortcut which allows for suspending?