choices:
- 1. Backup everything. Use a live CD etc with restore program on it.
- 1. Backup home directory. Reinstall OS then recover home directory.
- 1. Backup home directory, package manager status, /etc. Reinstall OS then recover home directory ....
I do 2 to minimise on size/time of backup, and impotent /etc stuff backed up in /home using revision control.