Thinking about it, I actually would like to change my suggestion:
I would paste the node basically at the same position plus some small, fixed offset to the bottom right. That makes it comparable to a lot of other graphical software.
Also, I would hate auto-arrange of a bunch of carefully arranged and copy-pasted nodes. Insetad, I would paste them in exactly the same layout as the copied nodes, but again offset to the bottom right a couple of pixels (and selected, of course, so the user can immediately drag them away).
Martin
Martin