title: How can I tell if a Magento request is for a frontend or backend page?
body: <p>How can I tell if the current request is for a backend or frontend page? This check will be done inside an observer, so I do have access to the request object if that helps.</p>
  <p>I considered checking <code>Mage::getSingleton('admin/session')-&gt;getUser()</code>, but I don't think that's a very reliable method.  I'm hoping for a better solution.</p>