Exposé to the rescue! When you hit F9, it shows all the previews at once. You can even set the text if you have a very specific need. You don't want to open too many windows at once, though. Depending on the size of your screen, the windows may be too small to see the details of each font (on my 20", its about 32 windows).
Then when you find the typeface you want, you can activate it by bringing that typeface's window to the front with a click. Don't forget to go to the Preferences to set Font Book to copy when installing. Font Book's not a full replacement for commercial font software, but far more cost effective for some of us.

