See this thread for info about how to automatically reinstall programs. Of course it doesn't help it your system is already completely destroyed.

rsync is also a handy tool for backing up your home directory to another computer. It only sends the changed parts of the files, so if you combine dpkg --get-selections and backup of your home dir you should get off relatively easily. I haven't tried it myself yet though

If you're using linux and you have your IT OS loaded on a MMC, you can mount the card with a reader and use dd to make 1:1 copy to disk and later restore it to another card.

With the current history of MMC corruptions having decent backups is crucial