The first release that has the new KDE 4 series as default.
From the annoucement:

2009 is a bold release which brings the new KDE 4.1 as the default desktop, along with a re-designed installer and Mandriva Control Center and many other new features. Other significant updates include GNOME 2.24, OpenOffice.org 3, Mozilla Firefox 3, and kernel 2.6.27. Key features include new graphical in-line upgrade capability, netbook compatibility, class-leading hardware support, and support for working with mobile devices.

Package-kit didn't made is as a default choice but developers encourage you to test it, and maybe, who knows, it will make it into 2009.1 / 2010.

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