Use Text Headings

Headers have a weighted importance with Search Engines so use the markup elements H1 - H6 for headings. Using graphics for headings allow you use a favorite typeface that may be supported in all browsers, but search engines are not going to give the image much consideration. Even if you use the alt attribute, as is required for standards compliance, to specify alternate text for heading images, that text will not be as important as real text in a heading element.

If you are not able to use real text, look at the variety of image or Flash replacement techniques that are available. With some style tricks and a little judicious planning and testing, type on the Web can be attractive, accessible and indexable by Search Engines.