The Media PC is built upon Fedora 7 including Fedora Extras, ATrpms and FreshRPMs repositories. The computer architecture is x86_64, but the i686 version is installed as there was not the correct architecture discs nearby. The Fedora was choosed because of being the most familiar with it. Nothing against other distros though.
The Gnome desktop was installed, again because of familiarity over KDE.
The configuration and tweaking were done mostly through a command line by using the ssh connection from the external computer.
The most upfront application installed, is the MythTV suite from the ATrpms repository.