Besides the ones with numbers, which are ByHost, there should be this one in your home folder Library/Preferences.
/Users/your user name/Library/Preferences/com.apple.systemuiserver.plist
The other thing I'd try is running Applejack which is a very useful little program for troubleshooting and repairing. It runs from Single User Mode. Hold CMD-S at the startup chime. Here's a short article explaining how it's used. (Also, be sure to read the Read Me.) It's very easy to use. You just follow the on screen prompts. First, just type in applejack and press return. To begin with, I'd only run it only for steps 3 and 4, which will do a relatively light cache cleaning and check for corrupted Preference files. Doing it this way, you'll also be able to run those steps for your user, not just the system. If that doesn't help, you can run it for deeper cache cleaning by typing in applejack AUTO and let it run through a full sequence of tasks. Note: that if you do a deeper cache cleaning, you can expect the system to run a bit slower until those caches are rebuilt.
http://reviews.cnet.com/8301-13727_7-10334620-263.html?tag=mfiredir
Download
http://applejack.sourceforge.net/