Restrict wp-admin access to a few roles

You may want to deny access to wp-admin to subscribers, since they haven’t too much to do inside wp-admin, right? It is quite easy to deny access to them, just use this snippet:

<?php
	function restrict_access_admin_panel(){
		global $current_user;
		get_currentuserinfo();

		if ($current_user->user_level <  4) { //if not admin, die with message
			wp_redirect( get_bloginfo('url') );
			exit;
		}

	}
	add_action('admin_init', 'restrict_access_admin_panel', 1);
?>