It's that time of year again - a new release of the desktop environment that has travelled a long road from its humble beginnings as a somewhat shaky 4.0, to today's 4.5 release as an already fully grown and mature desktop environment. Improving the stability, usability, and performance of features introduced in earlier versions was the main goal for 4.5.
WebKit is slowly but surely becoming a full citizen of KDE land as a welcome alternative to khtml. "After years of work, the integration for WebKit has been come part of our libraries. WebKit now provides a integration with password storage and other features in Konqueror, the KDE web browser. Other applications can make use of WebKit to display content with the same level of integration as KHTML."
A lot of work has been put in cleaning up the notification area, which looks a lot cleaner now thanks to monochromatic icons. Kwin can do tabbed windowing now, but since it relies heavily on toolkit support, it only works for Qt applications.
Lots of other stuff in there, so be sure to take a peek.