For CMS, our minds must be focused on two names, namely Joomla and Drupal. Currently Joomla and Drupal is the best CMS in the world.
Lately there are very interesting news, WhiteHouse.gov is using Drupal now. Of course, this is a proud news for lovers of Drupal, because again there are influential sites in the world switch to using Drupal.
Previous large organizations the world have also used Drupal as: NASA, IBM and many more.
Does Drupal advantages when compared to other CMS? Read Drupal vs Joomla for the answer.