There's an Isaac Asimov quote: "If my doctor told me I had only six minutes to live, I wouldn't brood. I'd type a little faster." But if there really were accurate predictions for a person's lifespan, how would people change? Maybe medical science is on the verge of creating a pharmaceutical solution for a fountain of youth. We seem to be a long way from a cure for death, but at least a few people think immortality will be available to humanity (eg. Aubrey de Grey, Ray Kurzweil, etc.) in the next few decades. Here are a few links to the study of aging and its causes.
If you'd like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post