Broke? Fonts completely messed up. Simple, yet important, math symbols like asterisk (\ast) and theta (\theta) didn't work anymore.
I tried updating the teTeX distribution with Fink, which is how I originally installed it. That didn't work. Partially because, to my chagrin, teTeX is no longer supported. Also, my Fink seems to be sick thanks to the Leopard upgrade. Fink selfupdate hasn't really worked for me either.
After tinkering a bit more with Fink and Macports (which seemed to require me upgrading to the latest XCode 3.0), I gave up trying to install LaTeX via package manager. I manually installed the latest-and-greatest Mac LaTeX engine: MacTex-2007. That seemed to fix TeXShop for me.
However, it didn't fix LaTeX Equation Editor, which I use for Keynote presentations. The fonts were still all jacked and simple symbols weren't being displayed properly still. What's more, a more complicated version of LaTeX Equation Editor, LaTeXiT wasn't working either. And yes, I changed the location of the executables in the preferences. And yes, I removed the previous installation of TeTeX with Fink.
After some more searching and discovery I figured it out.
According to this page, font caches are being corrupted. Please go ahead and add LaTeX Equation Editor to the list of programs that seem to be screwing up the font cache. Try rebooting. If that doesn't work try running the following commands from the terminal:
sudo rm -rf `lsof | grep com.apple.ATS/annex.aux | grep Finder | cut -c 66-139`
sudo rm -rf /private/var/folders/*/*/-Caches-/com.apple.ATS
LaTeXiT should now work. If you start using LaTeX Equation Editor, LaTeXiT will break again. The key solution: don't run Equation Editor ever again. Use LaTeXiT. Please note that other LaTeX programs which are not widely supported may cause the same font problems.