Keeping it simple
Careful design can give a site a distinctive look and set a mood, but care must be taken not to overwhelm the site's content.
"A website should communicate"
The purpose of a website should be to communicate its content, not to impress visitors with the wonderful design. Like good typesetting in a book, a good site design is one that supports the information without distracting the reader.
I rarely use graphics in place of text. Usually it's just a company logo at the top of the page. Some people will go on about machine readability and download times, but there are two other good reasons: Plain letterforms often look better than funky display fonts and if you need to create a graphic every time you add a headline or a menu item, you will add considerably to the time and cost of updating your site.
I have considered using the php graphics tools to automatically generate rendered text; Care would need to be taken to make sure that generated images were cached to keep the server loading down, and the arguments about readability and download times would still apply.