Restoring package selections
I have to say I just love apt-get way of package management. Especially that you can just save the list of packages you have installed
dpkg --get-selections > pakete.log
and with just a few commands bring your system (or another machine) to the same state again.
dpkg --set-selections < pakete.log dselect update dselect install
Also note that it might be useful to copy your /etc/apt/sources.list