In my opinion, the "big CMS" solutions like WordPress, Drupal and Joomla have become too bloated and confusing for the end user. My clients love Concrete5, which uses simple in-context editing and point/click/drag all wrapped up in a shiny interface.
Using Concrete5, I've cut my training time in half and the number of "editing support" requests from clients has decreased greatly. If you find yourself spending large amounts of time training and supporting your clients on one of the bigger CMS' then I'd give Concret5 a test drive.
Plus, it’s easy for developers to extend, theme and use Concrete5 to create larger web applications.
Try it at http://bit.ly/concrete5cms