My problem: Excel and Word 2004 would not start up. Each would crash every time. I thought the problem might be font-related, because Excel would tell me there was a corrupt system font (there really wasn't). FontBook was reporting similar problems.

Based on recommendations at the MacFixit web site, I installed Font Finagler 0.5.3 and ran it once. Excel and Word have since started up and worked without problems, the way they used to.

What more can I ask? And it's cheap, too, at $10.

I should add that my membership at MacFixit has paid for itself many times over, since I downloaded and read the members-only ebook "Be Your Own Mac OS X Troubleshooting Guru". It taught me many things, including the existence of easily corrupted font caches.