After the 9.3 install KDM was replaced by the ugly grey XDM by some unknown magic. To fix it change in /etc/sysconfig/displaymanager DISPLAYMANAGER="xdm" into DISPLAYMANAGER="kdm".
Of course in ~/.kde/share/apps, but if you have one hundred kde apllications and the programmers didn't manage to come up with a descriptive name for the configuration directory, you are in trouble. KAdressbook stores the data in ~/.kde/share/apps/kabc Additonally there might be for all applications (and there is for KAdressbook) the rc configuration file in ~/.kde/share/config/ ~/.kde/share/config/kaddressbookrc
I have one encrypted partition that was created under SuSE 9.2. After a fresh install of 9.3 (not an update) the mounting of that partition during bootup failed. I could, however, still mount it manually later using another loopdevice. To fix this, I had to change the encryption algorithm in /etc/cryptotab from twofish256 to twofishSL92. More detailed information.