Hide Trackbacks/Pingbaks if none exists

I am using a helper function for that.

functions.php

/**
 * Count amount of pingbacks + trackbacks for a post.
 *
 * @param int $post_id Post ID for comment query. Default is current post.
 * @return int
 */
function t5_count_pings( $post_id = NULL )
{
    $pings    = 0;
    $comments = FALSE;

    if ( NULL !== $post_id )
    {
        $comments = get_comments(
            array (
                'post_id' => $post_id, # Note: post_ID will not work!
                'status'  => 'approve'
            )
        );
    }
    elseif ( ! empty ( $GLOBALS['wp_query']->comments ) )
    {
        $comments = $GLOBALS['wp_query']->comments;
    }

    if ( ! $comments )
        return 0;

    foreach ( $comments as $c )
        if ( in_array ( $c->comment_type, array ( 'pingback', 'trackback' ) ) )
            $pings += 1;

    return $pings;
}

comments.php

if ( $num = t5_count_pings() )
{
?>
<h2 id="pingbacks"><?php
    printf( _n( 'One pingback', '%d pingbacks', $num, 't5_theme' ), $num );
?></h2>
<ol class="pinglist ■ sans-font">
<?php
wp_list_comments(
    array (
        'type'     => 'pings',
        'style'    => 'ul',
        'callback' => 't5_list_pings_callback'
    )
);
?></ol>
<?php
}

Now, if there are no pingbacks and no trackbacks $num = 0, and the markup for the list will not be printed.

You can use the function with a post ID to count the number of pings for another post than the current page like this: t5_count_pings( 12345 ).