Soliciting Advice on Baby Names?

So far, my hubby and I have decided on the first name Micah. Now, we just can't seem to think of a middle name. The name Micah will be unisex because it has special meaning to us. But we just cannot seem to come up with a middle name. I want something unique and with meaning. It can be a name from someone in history that made a positive impact. Or a name from someone that changed made a difference in the world. Any ideas? Thoughts? Suggestions?