Concrete5 is an extremely easy to use CMS that has a fairly simple mode of operation and can be employed to power various genres of websites, including blogs, portfolios and enterprise sites.
It comes with a WYSIWYG Editor and in-context editing toolbars, along with drag and drop support, native Flash support as well as Youtube, Google Analytics and Google Maps integration.
Concrete5 also offers native SEO in the form of clean URLs, RSS syndication and pre-formatted dynamic HTML tags.