Yes, Todd, I’m posting an update from work. This’ll save me from wasting time on Google later in life.
Use the command dpkg --get-selections to generate a list of all the installed packages. If you want to replicate a system quickly (say, for disaster recovery or system deployment), redirect the package list to a file (dpkg --get-selections >packagelist). Then, as long as you have a copy of the file, you can install a minimal Debian system and turn it into a replica of the other system with nothing more than an Internet connection and a few commands:

dpkg --get-selections |sed 's/\(de\)*install/purge/' | > dpkg --set-selections
dpkg --set-selections dselect install

And they say Windows’ TCO is lower than Linux…