Just wanted to recommend SilverStripe CMS and the SilverStripe Framework (previously saphire). I've tried to bend Wordpress to a CMS role, and have experience developing and maintaining a Drupal, Joomla CMS site and made some sites using CodeIgniter PHP framework (and rolled many from scratch). I tried Squarespace (if you want to spend money).
However SilverStripe is so easy to manage content with. Designers can take an existing template with stylesheets and get a basic working site going within the hour. Developers can use the extensive framework and feature set and expand from there, it's very elegant.
NegativesAt the moment the documentation is not yet up completely up to date with SS 3.0 (released end of june), and you will be googling the API and documentation sites quite a bit in order to piece the various components together. Also I've asked two questions on the forums without reply (although most questions seem to get good responses generally).
PositivesThat said, it's used by it's commercial developer to create and maintain sites for major New Zealand's major companies and organisations.
You can drag and drop images into an image field. You can then use Image.SetWidth(300) in your template and it will generate appropriate derivatives. You install one module and it will generate a full REST webservice based on your data. You add a few lines and your list of news items are now also exposed as an RSS feed. etc.
You will see many more sites from me in the future based on this.
Is there anyone here that have used it for any projects?