You can filter the default comment_form
arguments (which is what’s causing the “leave a reply”).
Just drop this in functions.php
or in a plugin file. It would probably be better to put it in a plugin and keep your twenty eleven theme unedited (read: easily updated).
<?php
add_filter( 'comment_form_defaults', 'wpse33039_form_defaults' );
function wpse33039_form_defaults( $defaults )
{
$defaults['title_reply'] = '';
return $defaults;
}