I said before I had no problems, but it turns out I do. Disk Utility is broken for me, too. When I first tried to load it, the window appeared, but it hung before the contents were displayed. I had to force-quit it, and when I did, it stayed in the Dock for some reason. I went to Activity Monitor to check on it, and it wasn't loaded. So I quit the Dock, and when it came back it was normal (i.e., no Disk Utility icon).
Now when I try to load Disk Utility again, I get a dialog box in the Finder that says "An unexpected error occurred (error code -600)". Disk Utility doesn't even begin to load.
I used the combo updater.
Edit: I've now tested this with my "error tester" user account, and it has the same problem. So I doubt it has anything to do with my personal settings.