This might be useful on super search, but as a general addition to all node links I would say no. It would take up too much space and make things too hard to read for my tastes.

How about adding the node id as the title attribute of the link? That way it would appear when you hover the mouse over it in many browsers.

Personally, I just stick the mouse over the link and look at the node id that's shown in the URL on the status bar :-)