Sympathy for our Enemies?

At the model seder we practiced spilling out ten drops of wine from our glass, which we do at our seders to indicate that even though the Egyptians were our enemies, they were still human beings, created by God. I even noticed that one student became upset when another student began to suck the juice off his finger, because he felt strongly that the point was for us not to gain any joy or benefit from it. What do you think is an appropriate way for us as Jews to react to the death of an enemy? If someone like Hassan Nasrallah, leader of the Lebonese terrorist group Hezbollah, were to die tomorrow, how should we react?