The WP global variable $pagename should be available for you, I have just tried with the same setup you specified.

$pagename is defined in the file wp-includes/theme.php, inside the function get_page_template(), which is of course called before your page theme files are parsed, so it is available at any point inside your templates for pages.

EDIT:

• Although it doesn’t appear to be documented, the $pagename var is only set if you use permalinks. I guess this is because if you don’t use them, WP doesn’t need the page slug, so it doesn’t set it up.

• $pagename is not set if you use the page as a static front page.

• This is the code inside /wp-includes/theme.php, which uses the solution you pointed out when $pagename can’t be set:

  $pagename = get_query_var('pagename');
if ( !$pagename && $id > 0 ) {
// If a static page is set as the front page, $pagename will not be set. Retrieve it from the queried object
$post = $wp_query->get_queried_object();
$pagename = $post->post_name;
}

NOTE: This answer was originally posted at StackOverflow.com by AJJ