I can reboot okay, but when I shut down the computer it goes through and I see the shutting down screen and it gets to the very end of everything (I think - the progress bar is at the end) and it just hangs there and my computer never shuts down. I have an ASUS P5GD1 motherboard.
The symptom of this particular bug, failure to power off when shutting down, is specific to the hardware and BIOS used. So while many people may have the same symptom each should be a separate bug. The bug report should contain the information requested at http://wiki.ubuntu.com/KernelTeamBugPolicies and the output of 'sudo dmidecode'. A new bug report's title should contain information about either your motherboard or system make and model.