For a quick look at the active fonts on your computer, check out It loads your fonts into its memory, shows you usefully-sized samples of them, then lets you see your own text in those fonts.

It can also display a table containing all the glyphs in any selected font, show you a questionably useful example of the metrics for the first few letters in the font, and display paragraphs of body text in several point sizes.

For a quick peek into any active font, or to see how various fonts will look on a Web page or computer display, MyFontBook is a fantastic free resource.