Today, I read an article on Slate, "How we read online," by Michael Agger. The article reports a study performed by Jakob Nielsen who is a usability expert and discusses topics such as eye-tracking research, web design errors, and banner blindness.
Jakob's study makes some good points on presentation. While I don't agree with all of his beliefs, overall, Jakob's suggestions are worth noting.
Additionally, I inform clients all of the time about the importance of eye-tracking. In print media, the eyes are limited to the page's edges. On the web, however, if the page is not designed properly, then a visitor's attention could be hard to keep and diverted quite easily. Good web designers are typically able to draw the attention of visitors to certain aspects of pages and "encourage" specific navigational routes to increase the chances of conversion - or, simply, getting information about the user by them completing a form or something of that nature.
Quality does matter, especially if your site is one-in-a-million. How does your site stand out? What kind of impact does your site make?