$count loop

<section>

    <div id="news">

        <?php $list_news = new WP_Query('cat=3&showposts=-1'); ?>
        <?php $count = 0; ?>
        <?php while ($list_news->have_posts()) : $list_news->the_post(); $do_not_duplicate = $post->ID; ?>
        <?php $count++; ?>
        <?php if ($count == 1) : ?>

        <div class="col_one">

            <article>

                <h3><a href="<?php the_permalink(); ?>" ><?php the_title(); ?></a></h3>

                <?php the_content(); ?>

            </article>

        </div> <!-- col_one -->

        <?php elseif ($count == 2 || $count == 3 || $count == 4) : ?>

        <div class="col_two">

            <article>

                <h3><a href="<?php the_permalink(); ?>" ><?php the_title(); ?></a></h3>

                <?php the_content(); ?>

            </article>

        </div> <!-- col_two -->

        <?php else : ?>

        <div class="col_three">

            <article>

                <h3><a href="<?php the_permalink(); ?>" ><?php the_title(); ?></a></h3>

            </article>

        </div> <!-- col_three -->

        <?php endif; ?>
        <?php endwhile; ?>

    </div> <!-- end news -->

</section>