You might be interested to know that the original meaning of the phrase 'An eye for an eye' meant ONLY an eye for an eye. It was supposed to encourage proportionate retribution, so if someone cut your eye out, you wouldn't go and stab them to death, you would (only) cut out their eye. Also, I guess that you don't have to choose between these two ways of living. Treating other people as you would like to be treated is a good way of getting on in the world, like a kind of mutual assurance, but for someone like Jesus, his moral code is a lot more radical and not at all reciprocal. You have to do good to people who have done you no good at all. It's a brave thing to be able to live like that.