I think more agnostics and atheists would recognize the contribution of Jesus more often if Christians would't point to it as evidence of the Holy Spirit working on the hearts of us poor atheists and agnostics. So with that disclaimer I want to wade into this pool that has more than a few pitfalls. (Baptismal metaphor intentional)
I have been contemplating the idea of having empathy as a more influential basis for ethics for a while and it has been interesting to see others exploring this idea. Jesus establishes this basis without referring to it directly with his statement to love your neighbor as yourself. This appears to be a direct reference to one's ability to project one's experience on another.
Jesus further expands this idea of loving one's neighbor with the clever story of the good Samaritan by expanding the definition of our neighbor to all of humanity. The misdirection of the story provides a rational trap by which the listener has to answer the question of who is one's neighbor by what they do rather than their class or race.
In this TED video Jeremy Rifkin explores the evolution of empathy...
The ideas that stand out here for me are that humans are soft wired to be good to each other and we can evolve to be wired differently. We can also have this soft wiring suppressed. I think some forms of religion suppress this by redefining who our neighbor is and recreate new forms of class that don't deserve empathy within its modified world view.
Sam Harris in another TED video talks about the rational basis for ethics along the same lines.
I think if the Bible was only the phrase love your neighbor as yourself and the parable of the good Samaritan the message would be a lot clearer. As we engage in the very human dialog of what it means to live with each other and to find meaning without destroying each other I would hope we could learn how to recognize what works from reason informed by empathy.