I've noticed that the best way to handle an internet argument (most often on Facebook) is simply to ignore the person all together and allow them to keep talking. Minus your responding to their comments/insults.
Seriously, why give them the time of day? It often makes them twice as angry, but then you remain completely out of the picture, and you don't become angry at all.
Is ignoring better than trolling? Or is ignoring trolling in it's own right? What do you guys think?