display only one comment in node page
First install and configure "Comment goodness" module - it will allow you to sort comments to display newest first.

Then in your template.php create.

function THEME_preprocess_comment_wrapper(&amp;$variables) {
   // Remove pager.  
   unset ($variables['content']['comments']['pager']);
   // Leave only latest comment.
   $last_comment_id = reset(element_children($variables['content']['comments']));
   $variables['content']['comments'] = array (
     $last_comment_id =&gt; $variables['content']['comments'][$last_comment_id]
   );
}