Comment 8 for bug 1172018

I had the really same issue, except that I could reproduce it by simply clicking the "Log Out..." button.
I don't know if it is related to, but after each login I had a warning from hddtemp. I did the (not so) suggested:

 chmod u+s /usr/sbin/hddtemp

and now everything seems to work fine. I can logout normally and I opened up to 20 windows without crashes.