I found a tool that gives you search engine terms for the kind of site you have. It also tells you which terms are most popular.
Term Suggestion Tool - Overture (<!-- m --><a class="postlink" href="http://www.content.overture.com/d/USm/ays/ays_driveP.jhtml">http://www.content.overture.com/d/USm/a ... iveP.jhtml</a><!-- m -->)
Term Suggestion Tool - Overture (<!-- m --><a class="postlink" href="http://www.content.overture.com/d/USm/ays/ays_driveP.jhtml">http://www.content.overture.com/d/USm/a ... iveP.jhtml</a><!-- m -->)