Hi Bundy,
That the problem keeps recurring suggests that you have a corrupt font. This will corrupt Font Book's font cache and/or database. You'll need to root out the bad fonts to eliminate the problem.
Pull all fonts out of the /Library/Fonts/ folder and your user account at ~/Library/Fonts/. Just put them in a dummy folder on the desktop.
Replace all system fonts by installing fresh copies from the OS X Install CD/DVD. The instructions to do this are in
Font management in Mac OS X Tiger and Panther. It's the last section. This will put all new copies of the fonts that come with OS X on your hard drive.
Follow the steps in
Undoing Font Book to reset the application and clear its font caches once again. Run Font Finagler and clear the MS Office font caches.
With all new fonts, new font caches and a clean Font Book, everything should work normally. Delete any duplicate fonts from the dummy folder you created that reinstalling the fonts placed on your hard drive. That should leave only those you added yourself. Place them into the /Library/Fonts/ folder five at a time. If the problems return, you know at least one of the fonts you added is bad.