Tonite I just did my weekly "yum update" and I was happy to find that KDE has been updated to version 3.5.1! But when I restarted my computer, GDM didn't work as usual. Everything was gray and the screen was divided in two. I did ctrl-alt-backspace to get out of it and when I got back to, I got a warning that my greater (GDM) crashed and another greater (XDM) was launched instead). Hopefully, I'm able to get into KDE and Gnome when it falls back to XDM.
Oh, I'm not the only one having the issue. A guy in #fedora on freenode experiences the same problem since he updated to KDE 3.5.1.