Pimcore: Opensource & Zend+ExtJS Powered CMS
Pimcore is a feature-rich and robust PHP content management system, that is built with Zend Framework, for creating and managing digital content + assets.
The interface is powered with ExtJS and almost all editing is done via drag 'n' drops.
It is possible to work on multiple documents at the same time with the help of the multi-tabbed usage.
Pimcore is also a product information management framework (PIM) which means true multi-channel publishing and integration into ecommerce systems like Magento and OXID eSales.
The application is powerful on controlling digital assets as well. It can be integrated to the desktop using WebDAV or to the 3rd party systems via web services.
For images, it can analyze them automatically (EXIF data), create thumbnails and enable you to edit them (rotate, crop, etc.).
If the assets are documents, it offers web-previews using a Scribd account. And a similar preview works for videos using Youtube.
Pimcore has many other advanced features like versioning, built-in caching, permission-based user management, multilingual interface and much more.