Dolphin, KDE’s file manager, which also deputizes as a Web browser, is probably the most feature-rich file manager on any desktop environment. Here, it is shown with its beautiful icons.
ROSA Desktop 2012 Dolphin File Manager

The developers of ROSA Desktop have added one more feature to Dolphin. That feature, is the integration of KLook, a multi-file type viewer that I already wrote about (see KLook: A Swiss Army knife of media type viewers). What KLook brings to Dolphin, is the ability to view images, text files, and play audio and video files in a slideshow fashion without leaving Dolphin. It is a very cool application.
ROSA Desktop Dolphin KLook

While using KLook, you can switch to thumbnail view by clicking a button on the top bar. You can also switch to fullscreen mode.
ROSA Desktop KLook Thumbnail Viewer

Another cool application available only on ROSA Desktop 2012 beta, is ROSA Media Player or ROMP. Aside from being able to play and video files, it also gives you the ability to record or capture your desktop in WebM format. A similar feature was introduced in GNOME 3.4 (see 3 minutes with GNOME 3.4 built-in screen recorder).
ROSA Media Player Capture Desktop

ROSA Desktop inherits Mandriva’s Control Center, with its powerful graphical management applications.
ROSA Desktop 2012 Control Center

And you get access to thousands of applications, including free and non-free ones. No need to look for third-party repositories elsewhere just to play encrypted video DVD’s.
ROSA Desktop 2012 Repository Manager

Writing about a KDE desktop is never complete without throwing in a few screen shots of the KDE Plasma Netbook interface. The one below shows the main KDE Plasma Netbook interface.
ROSA Desktop 2012 KDE Netbook

This one shows installed Office applications.
ROSA Desktop 2012 Netbook Office Apps

And finally, this one shows installed Internet applications.
ROSA Desktop 2012 Netbook Internet Apps