Applying different formatting to just the first post on the first page

<?php if (have_posts()) : ?>
  <?php $post = $posts[0]; $c=0;?> 
 <?php while (have_posts()) : the_post(); ?> 
   <?php $c++;  if( $c == 1) :?> 
 <h1>The first post on the main index page</h1>
  <?php the_title(); ?>  <?php the_excerpt(); ?>  
  <?php else :?>  <h2><?php the_title(); ?></h2> 
 <?php the_content(); ?>  <?php endif;?> 
   <?php endwhile; ?>    <!-- page nav -->

More -->
http://wordpress.org/support/topic/302408?replies=6