Mind or Soul?

When John asked us in class which we would rather choose to save (mind or soul), I immediately thought mind because it's what makes me... well, me. Your brain does all these weird funky things and your mind is there to interpret and experience it all.
So if someone else's brain goes into a new body, I'd feel like that person is now the person whose brain is inside the body.
But what is soul? I left class puzzled and wondering about this. The more I thought about it, the more confused I got. I thought about how if your mind makes you who you are, then what exactly is your soul there for? Do we even have souls? Well the next thought that came to mind was ghosts. If we don't have souls then what are ghosts?? Souls have to exist, because ghosts are (or at least this is what I believe) the souls of people who have passed away. Souls are that spirit and essence of a person once their functioning minds are no longer here on Earth.

But wait, I'm still confused.

What role does your soul play when you're still alive then? Is it just the idea or essence of us as individuals and it just magically pops out once we die? Is it in us right now even though we can't really prove that it's there?
Or am I just thinking way too much?

pic: http://www.dreamstime.com/human-mind-image1208909