Back on Mac OS 9 I used to have a great font browsing tool that allowed me to preview hundreds of fonts very quickly. Each font would only take up one line of text and everything was on the same page. It could take some time to launch but you could simply scroll through all these lines to see every font very quickly.
I have been using FontBook for a long time but I'm not sure if there's a way to do this with FontBook... or with a font browsing app.