The following error makes me frown : default value in power.sh potentially kills laptop disks. When switching to battery power, /etc/acpi/power.sh issues the command hdparm -B 1 to all block devices. This leads to extremely frequent load cycles, thereby drastically limiting the life cycle of a laptop disk.
It seems this was a month ago on Digg, but I still haven't found out if this is valid or not. The bug thread ends on Oct 13th, so maybe this is solved in Gutsy ?