Coherence is a set of DLNA/UPnP devices, like MediaServer and MediaRenderer. In addition, it includes a well-designed framework to extend other applications with DLNA/UPnP functionality. It also has an emerging DBus API, enabling these applications to participate in digital living networks. It supports Playstation 3 (PS3), XBox, and many other devices.
KatchTV is an "Internet TV" application for KDE. It makes it easy to subscribe to "TV" channels from all over the Internet in the form of podcasts, so that you can browse channels, download shows, and watch them, all from one convenient interface. It is very similar to Democracy TV, but focuses on KDE integration, using KHTMLPart and embedded players such as kaffeine. It's much faster and lighter on resources if you run a KDE desktop without GTK apps. Installation is easy as long as your distribution has PyKDE and PyQt.