Media Centers

There are a few alternatives to MythTV that can be considered.

MythTV is the most feature-rich and advanced Media Center available for Linux today. It’s Live TV support is better than all. (opensuse packages) - more moose about mythtv

Elisa from Fluendo is a new and coming project. It’s being built from the ground up on top of GStreamer.
(opensuse packages) - more moose about elisa

Linux MCE is another project that deliver Media Center features to Linux.

Freevo
It provides everything you need for a media center and at the same time is easy to maintain and to extend because its not one big monolithic app but rather a frontend for various applications. Because it is written in python its very easy to fix and extend. (opensuse packages)
GeeXboX project has joined the Freevo team to create a Live-CD based on Freevo.