I found out a little trick to update your list of installed fonts in Mac OS X - which is useful if you have many installed already, and want to add more to use immediately. It's also a good way to find corrupt fonts (or at least fonts that OS X thinks are corrupt) and weed them out without having to restart.
- Open the Terminal and TextEdit.
- Type "sudo fcache" in the Terminal, giving your password when it asks.
- fcache only (it seems) outputs "problems" to the Terminal window. It guesses at weights for a few fonts, like italics, which doesn't seem to be a serious issue, but it does reveal how many fonts have serious errors as well. For some errors, it will give the name, and for others it won't (especially for Postscript fonts that have the "-- font --" problem that many seem to have.).
- Remove any suspect fonts if you have problems, and add any new fonts you want to use.
- Type some text in TextEdit, and open the font panel to see what your options are.
- Repeat steps 2-5, and note that your new fonts are now available, without having to quit anything. This is also a way to narrow down which fonts do have problems - if only we had labels to color code them!