I know I'm a week behind about this, but I just came across the link via Gadgetopia: Open-source PHP applications that changed the world. The CMS related applications that were determined world changers are listed below.
When you split the list into three sections, you get the feeling that PHP-Nuke, ezPublish, and osCommerce have been around for a very long time. More importantly, you begin to think that it is time for Gallery, Drupal, and MediaWiki to either be seen as mature applications or for those applications to finally grow up.
Bryan Ruby is the owner and editor for CMS Report. He founded CMSReport.com in 2006 on the belief that information technologists, website owners, and web developers desired visiting sites where they could learn about content management systems without the sales pitch. Besides this site, you can follow Bryan at Google+ and Twitter.