Magento: Get user Details in admin panel

Sometime we need to show some extra information about user: you can do this task with the following code:
You can get admin user data like ID, Email, First Name, Last Name, User Name, Password

<?php
// For complete data array
$userArray = Mage::getSingleton('admin/session')->getData();
// For particular data
$user = Mage::getSingleton('admin/session');
$userId = $user->getUser()->getUserId();
$userEmail = $user->getUser()->getEmail();
$userFirstname = $user->getUser()->getFirstname();
$userLastname = $user->getUser()->getLastname();
$userUsername = $user->getUser()->getUsername();
$userPassword = $user->getUser()->getPassword();
?>