Magento : Get Customer Email in Success Checkout Page

<!-- path : \app\design\frontend\theme\default\template\checkout\success.phtml -->

<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Academic Free License (AFL 3.0)
 * that is bundled with this package in the file LICENSE_AFL.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/afl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to [email protected] so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magento.com for more information.
 *
 * @category    design
 * @package     base_default
 * @copyright   Copyright (c) 2006-2015 X.commerce, Inc. (http://www.magento.com)
 * @license     http://opensource.org/licenses/afl-3.0.php  Academic Free License (AFL 3.0)
 */
?>
<div class="page-title-confirm">
    <h1><?php echo $this->__('Confirmation') ?></h1>
</div>
<span class="step"><?php echo $this->__('Step 3 of 3') ?></span>
<?php echo $this->getMessagesBlock()->toHtml() ?>
<h2 class="sub-title-thank"><?php echo $this->__('Thank You for Your Order') ?></h2>

<div><?php echo $this->__('We have sent your order confirmation to') ?></div>

<?php
    $order_data = Mage::getModel('sales/order')->loadByIncrementId($order_increment_id);
    echo $order_data->getShippingAddress()->getEmail();
?>

<?php if ($this->getOrderId()):?>
<?php if ($this->getCanViewOrder()) :?>
    <p><?php echo $this->__('Your order ID is') ?></p>
    <div><?php echo $this->__('%s', sprintf('<a href="%s">%s</a>', $this->escapeHtml($this->getViewOrderUrl()), $this->escapeHtml($this->getOrderId()))) ?></p>
<?php  else :?>
    <p><?php echo $this->__('Your order ID is %s', $this->escapeHtml($this->getOrderId())) ?></p>
<?php endif;?>
    <p><?php echo $this->__('You will receive an order confirmation email with details of your order and a link to track its progress.') ?></p>
<?php if ($this->getCanViewOrder() && $this->getCanPrintOrder()) :?>
    <p>
        <?php echo $this->__('Click <a href="%s" onclick="this.target=\'_blank\'">here to print</a> a copy of your order confirmation.', $this->getPrintUrl()) ?>
        <?php echo $this->getChildHtml() ?>
    </p>
<?php endif;?>
<?php endif;?>

<?php if ($this->getAgreementRefId()): ?>
    <p><?php echo $this->__('Your billing agreement # is: %s.', sprintf('<a href="%s">%s</a>', $this->escapeHtml($this->getAgreementUrl()), $this->escapeHtml($this->getAgreementRefId())))?></p>
<?php endif;?>

<?php if ($profiles = $this->getRecurringProfiles()):?>
<p><?php echo $this->__('Your recurring payment profiles:'); ?></p>
<ul class="disc">
<?php foreach($profiles as $profile):?>
<?php $profileIdHtml = ($this->getCanViewProfiles() ? sprintf('<a href="%s">%s</a>', $this->escapeHtml($this->getProfileUrl($profile)), $this->escapeHtml($this->getObjectData($profile, 'reference_id'))) : $this->escapeHtml($this->getObjectData($profile, 'reference_id')));?>
    <li><?php echo $this->__('Payment profile # %s: "%s".', $profileIdHtml, $this->escapeHtml($this->getObjectData($profile, 'schedule_description')))?></li>
<?php endforeach;?>
</ul>
<?php endif;?>
<div><?php echo $this->__('Please note for bank transfer you need to  confirm your payment through') ?></div>
<div><a href="#"><?php echo $this->__('payment confirmation') ?></a><span><?php echo $this->__('page or from the link in your email') ?></span></div>
<!-- <div class="buttons-set"> -->
    <!-- <button type="button" class="button" title="<?php //echo Mage::helper('core')->quoteEscape($this->__('Continue Shopping')) ?>" onclick="window.location='<?php //echo $this->getUrl() ?>'"><span><span><?php //echo $this->__('Continue Shopping') ?></span></span></button> -->
    <div title="<?php echo Mage::helper('core')->quoteEscape($this->__('Continue Shopping')) ?>" onclick="window.location='<?php echo $this->getUrl() ?>'"><span><span><?php echo $this->__('Continue Shopping') ?></span></span></div>
<!-- </div> -->