Well, as told by Tom Deleu, yes, though Drupal is very capable and strong CMS but it is tough and complicated to work on. Coming to another option of CMS that is Wordpress. Though it is very easy to develop a content based websites with wordpress but with very limited scope and flexibility.
As per your requirement my vote will also go to Joomla. It is very user friendly, optimized and a CMS you can rely on. Small applications as mentioned by you like "mailing system", "File system" etc. suits joomla more than others.
