I also get this behavior on my HP nw9440. Acpi works flawlessly on the live cd. I suggest everyone having this problem should pop in the live cd and see if the battery meter works. If so, then its a regression and it should be easier to fix.
Other acpi events that work on the live cd but not on the currently installed system: ac plug / unplug sleep button screen brightness buttons battery status button (? its a picture of a battery and when i press it, a balloon pops up telling me how much juice I've got left.) -- ACPI Monitoring Fails in Some Laptops https://launchpad.net/bugs/30785 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
