How to hide node's title in view mode

Okay, here's what I've come up with so far:

_{hide_node_title.info}

; $Id$
name = Hide Node Title
description = "Provides option to suppress node titles on a per node basis."
core = 6.x
package = Other

_{hide_node_title.install}

// $Id

/**
 * @file
 * The install file for Hide Node Title allows the module to install (and uninstall) itself. This is required as this module uses its own table.
 */

/**
 * Implementation of hook_install().
 */
function hide_node_title_install() {
  drupal_install_schema('hide_node_title');
}


function hide_node_title_schema() {
  $schema['hide_node_title'] = array(
    'fields' => array(
      'nid'        => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
      'hide_title' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0)
    ),
    'primary key' => array('nid'),
  );

  return $schema;
}


/**
 * Implementation of hook_uninstall().
 */
function hide_node_title_uninstall() {
  drupal_uninstall_schema('hide_node_title');
}

_{hide_node_title.module}

/**
 * Implementation of hook_perm().
 */
function hide_node_title_perm() {
  return array('hide node title');
}

/**
 * Implementation of hook_form_alter().
 */
function hide_node_title_form_alter(&$form, $form_state, $form_id) {
  // If we don't have permission to hide the title then we need to abort this alter now!
  if (!user_access('hide node title')) return;

  // Only alter node forms.
  if (isset($form['#id']) && ($form['#id'] == 'node-form') && arg(0) == 'node') {
    $form['hide_node_title'] = array(
      '#type' => 'checkbox',
      '#title' => t('Hide title'),
      '#description' => t('Optionally hide the title when this content is displayed.'),
      '#default_value' => $form['#node']->hide_node_title,
      '#options' => t('Hide'),
      '#weight' => -4,
    );
  }
}

/**
 * Implementation of hook_nodeapi().
 */
function hide_node_title_nodeapi(&$node, $op, $teaser = NULL, $page = NULL) {
  switch ($op) {
    case 'update':
      if (user_access('hide node title')) {
        db_query("DELETE FROM {hide_node_title} WHERE nid = %d", $node->nid);
      }
      // Fall through to insert is intentional!
    case 'insert':
      if (isset($node->hide_node_title) && $node->hide_node_title == 1 && user_access('hide node title')) {
        db_query("INSERT INTO {hide_node_title} VALUES (%d, %d)", $node->nid, $node->hide_node_title);
      }
      break;

    case 'delete':
      db_query('DELETE FROM {hide_node_title} WHERE nid = %d', $node->nid);
      break;

    case 'load':
      return array('hide_node_title' => hide_node_title_hide_title($node->nid));
    case 'view':
      drupal_set_title(($node->hide_node_title == 1) ? '' : $node->title);
  }
}

function hide_node_title_hide_title($nid) {
  return db_result(db_query('SELECT hide_title FROM {hide_node_title} WHERE nid = %d', $nid));
}

/**
 * Implementation of hook_preprocess_page().
 */
function hide_node_title_preprocess_page(&$vars) {
  $vars['title'] = ($vars['hide_node_title'] == 1) ? '' : $vars['title'];
}

hide_node_title_preprocess_page() isn't working and I don't know why, so I've resorted to using drupal_set_title() in hook_nodeapi. That means that the node title is removed from the <title> tag, but I'm using Page Title module and can put that back. Comments are welcome to improve this.

In the end, this provides an easy way to hide the node title without affecting other uses of the data.