I am also trying to restore GNOME as my desktop manager and have done everything that I did to make KDE my default desktop manager but in reverse and I can't get rid of KDE!
What other files do I need to change other than the /etc/sysconfig/desktop?
You don't say which Fedora you have but you can do it on the log in screen. For example F9 has an option at the bottom of the screen to choose the desktop.