That's kinda the basis of the question, as if push comes to shove you can plane wood with your cnc machine, you can cut wood down like a table saw, you can use it as a drill press... so if push came to shove, what is the one other tool you would find essential aside from the cnc.
While I have none of the other stuff, I am thinking one of those table sanders that has a belt and disk, as using a hand sander doesn't much allow for straight and even sanding.