The value of life

Is it ethical to talk about the “value of life” and put numbers on it? Why? Do all lives have the same value of life? What about people in different countries – should there be any difference? What about statistical versus identifiable fatalities – should there be a difference here? Is misperception of risk a form of irrationality or does it represent a more complex way of thinking about risks? Is it ok for people to have preferences about the types of risk that they take on, or should we compel them to minimize total risk?