ALSA bit me
I did an apt-get dist-upgrade a couple days ago, and couldn't reboot because of a bug in alsa-base (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=172583&archive=yes)
The solution was to comment out the typo line in /etc/devfs/conf.d/alsa
Was /bin/ed really the best editor I had? I didn't see anything else.
Note! Devfs reads all the files in the conf.d directory, so don't make a backup alsa file in the same directory, or it won't work ;)
Thanks to #debian channel user TBBle for recognizing my bug.