Page with http error (404, 403, ...) should diplay the current page title

In fact you can track theme easely if you use the google analitics module has it push a custom path (404.html and 403.html) to google analitics.

....
// Track access denied (403) and file not found (404) pages.
    if ($status == '403 Forbidden') {
      // See http://www.google.com/support/analytics/bin/answer.py?answer=86927
      $url_custom = '"/403.html?page=" + document.location.pathname + document.location.search + "&from=" + document.referrer';
    }
    elseif ($status == '404 Not Found') {
      $url_custom = '"/404.html?page=" + document.location.pathname + document.location.search + "&from=" + document.referrer';
    }
....