How can I retrieve multiple get_post_meta values efficiently?

I am looking for a solution to returning multiple get_post_meta values…

Current I am using a meta box array as follows:

$meta_boxes[] = array(
'id' => 'setlist',
'title' => 'Setlist Information',
'pages' => array('post'),
'fields' => array(
    array(
        'name' => 'Setlist 1',                  // field name
        'desc' => 'Entry 1',                                    // field description, optional
        'id' => $prefix . 'setlist_1',              // field id, i.e. the meta key
        'type' => 'text',                   // text box
        'std' => '',                                            // default value, optional
        'style' => 'width: 100px',              // custom style for field, added in v3.1
    ),
            array(
        'name' => 'Setlist 2',                  
        'desc' => 'Entry 2',                                    
        'id' => $prefix . 'setlist_2',              
        'type' => 'text',                                       
        'std' => '',                                            
        'style' => 'width: 100px',              
    ),

and so on so forth (i.e. setlist_3,4,5,6,7,8….)

In my single.php I have:

<?php if ( get_post_meta( $post->ID, 'rw_setlist_1', true ) ) : echo "<li>"; echo get_post_meta( $post->ID, 'rw_setlist_1', true ); echo "</li>"; ?>
<?php endif; ?>
<?php if ( get_post_meta( $post->ID, 'rw_setlist_2', true ) ) : echo "<li>"; echo get_post_meta( $post->ID, 'rw_setlist_2', true ); echo "</li>"; ?>
 <?php endif; ?>
 <?php if ( get_post_meta( $post->ID, 'rw_setlist_3', true ) ) : echo "<li>"; echo get_post_meta( $post->ID, 'rw_setlist_3', true ); echo "</li>"; ?>
 <?php endif; ?>
 <?php if ( get_post_meta( $post->ID, 'rw_setlist_4', true ) ) : echo "<li>"; echo get_post_meta( $post->ID, 'rw_setlist_4', true ); echo "</li>"; ?>
 <?php endif; ?>
 <?php if ( get_post_meta( $post->ID, 'rw_setlist_5', true ) ) : echo "<li>"; echo get_post_meta( $post->ID, 'rw_setlist_5', true ); echo "</li>"; ?>

The set-list values can range from 2 to 30…

Call me crazy, but I feel as if this method causes unnecessary and lengthy load times, am I right? So how would I go about creating a more efficient script for this that would check all the values in the array in a “simpler way”.

The way your code is setup is just wrong, you are making two database calls for each custom field and if you have between 2-30 fields like this then that means you make over 60 calls to the database which can be done with a single call using get_post_custom()
for ex:

$custom_fields = get_post_custom($post->ID);
for ($i = 1; $i <= 30; $i++) { 
    if(isset($custom_fields["rw_setlist_$i"])){
        echo "<li>"; 
        echo $custom_fields["rw_setlist_$i"];
    echo "</li>"; 
    }
}