A new eye tracking study done in Spanish by Mari-Carmen Marcos and Cristina González-Caro at Pompeu Fabra University in Barcelona and published July 2010 (Spanish PDF over here) was translated by Ani López reveals some new insights into searcher behavior.
The study shows that the search snippet, often the meta description from the site, is an extremely important factor for searchers. The study included 58 people of both genders and wide age range and tested informational, navigational, transactional and multimedia types of searches. The searches were done on Google, Google Images, Yahoo and Yahoo Images with a total of 22 tasks per person.
Here is the outcome of the study:
As you can see, the snippet is fixated over more than the title or the URL. Meaning the searchers spent more time looking at the snippet than the title or URL of the search result. This may imply that having a nice snippet, which is sometimes pulled from your meta description, is critical in increasing the chances of someone clicking on your search listing, instead of your competitors.