Hi, I update my Debian Sid more or less daily, and this week I got hit by this bug. After updating with synaptic and rebooting, kdm wouldn't start. Trying to "startx" would give the message " /etc/X11/X is not executable". Following the symlinks showed that, indeed, I was missing a xserver package. After installing xserver-xorg everything went fine, of course. Maybe your fix didn't arrive to the finnish mirror in time :-)
Anyway, thanks for fixing this, I do believe it's an important bug. I do have apt-listbugs installed to catch things like this one, but this time it didn't report anything about the X upgrade of this week... odd. I installed the x-window-system-core metapackage that I was missing, just in case ;-) Keep up the good work with Debian. Iago "Andûr" García