You can use graphics for headlines to introduce more variety into your text. The tradeoff for this flexibility is a longer download time for images, so keep your total file size in mind and use images for text just when you really need them. Color is another good way to make your text stand out. Experiment with it, keeping in mind that colors display differently in different browsers. Avoid underlining to highlight text.
Web surfers expect an underlined text string to be a hyperlink.