backup - How to back up my entire system?

If I want to make a backup of my entire OS (including but not just my home directory), how do I go about this?

Is it as simple as backing up everything in / and then when if I suffer a crash, just copying the files back over?
Will this cover grub, and how do I actually do this when the system is inoperable?

FILES

Refer to this howto: http://ubuntuforums.org/showthread.php?t=35087

In simple terms, the backup command is: sudo tar czf /backup.tar.gz --exclude=/backup.tar.gz --exclude=/dev --exclude=/mnt --exclude=/proc --exclude=/sys --exclude=/tmp --exclude=/lost+found /. Add more --exclude= parameters if you need to.

It will create an archive of all your files at /backup.tar.gz, which you can then copy over to another computer/drive and restore your files if the install goes pear-shaped. You can do it from a LiveCD, by mounting the "bad" system under /media or /mnt and running tar xf /path/to/drive/with/backup.tar.gz -C /mnt (substitute for the actual path to the "bad" system).

GRUB

This will not cover GRUB, however you can easily reinstall it by following this guide here. You only need to do steps Three and Four.