Immortality -- to me at least -- doesn't seem like it will end up providing that many benefits to humanity as a whole. Population control will become much more difficult, unless all over-aged males are somehow forced to undergo a vasectomy. And I highly doubt that people living longer will lead to increased productivity. On the contrary, I think that people will rely on welfare more and more as they age, not because of health, but because of burnout. The obvious solution to this is the creation of a general AI that provides the majority of humans with unlimited income for life. But then, if everyone is rich, people will quickly get bored after experiencing everything they're interested in, making immortality essentially useless!