Karmic Alpha 1's underlying technology for power management and laptop Fn key maps was moved from "hal" (which is going to be deprecated soon) to "DeviceKit-power" and "udev-extras". When testing Alpha 1, please pay particular attention to regressions in those two areas and report bugs.
(extract from http://www.ubuntu.com/testing/karmic/alpha1)
My Upup builds have HAL, but I have emasculated it. I haven't mentioned this before, but in the Woof builds I have my own script /etc/init.d/x_hal, plus I ripped out most of the HAL stuff from /etc/hal, reducing HAL to being as non-intrusive as possible.
HAL does complain in /tmp/xerrs.log, but it doesn't seem to cause any problems anywhere.
Comments:Posted on 11 Jun 2009, 20:16 by BarryK
hal vs devicekit
Here the original creator of HAL explains what is wrong with it, and introduces DeviceKit: