Full System Backup

I just had the... umm... pleasure of reinstalling Gentoo linux on my computer due to a hard disk crash. While my data files were relatively backed up, the system was all but not. I was wondering, since I have a DVD burner: can one easily burn a DVD of a running system? At present, I have just under 4 GB on the main partition and figured now would be a good opportunity to do so since it will fit on one DVD. I'd like to be able to just use some sort of "knoppix toram" if it fails again and copy over my system, run lilo, and have a functional box again.

Ideas/thoughts?