(Inspired by my my answer on Quora.)
Different people have very different answers, and emotional responses, to this question. Me personally? Absolutely I would live forever. And I think anyone who enjoys learning, growing, and being around people would agree (and I personally think that represents most people.) However, I think many of those same people would immediately answer “No” to this question.
Here’s how I think about it: If you asked someone “Would you rather die at 25 or 35?” they will answer 35. If you ask them “Would you rather die at 35 or 85?” they will answer 85, but with a tiny bit of hesitation. The hesitation almost always comes from fear: fear of aging/injury/loss of beauty, fear of loss, fear of the unknown — all sorts of fears; all of which are entangled with each other.
So here’s what I do: ask people “Would you rather die at 35 or 135, while also knowing that you wouldn’t age much physically, and that at least a few close relationships would live as long as you, in the same good health?” The response is usually a long hesitation, followed by “Well, 135. I guess?” I think this is akin to the preference of loss aversion over gaining something.
In other words, people don’t realize that when they say they wouldn’t want to live forever, they’re essentially also saying “Death is preferable to life, so I’d like to minimize life as much as seems reasonable; say, 60 or 70 years should be enough. There’s nothing worth living for after that point anyway (otherwise I’d want to live longer/forever).”