Do I really need the div class entry?

No specific markup is required in a theme. The only exception are themes published on wordpress.org, they have to follow the guidelines. And even there, <div class="entry"> is not required.

The only parts you have to use are these:

while ( have_posts() )
{
    the_post();
    print '<h2>' . get_the_title() . '</h2>';
    the_content();
    wp_link_pages();
}