I would happily settle for a few thousand years. Even a few hundred would be a major improvement over the grim darkness of the current wither-and-die-young system.

It's all a matter of what you do with the time. Back a couple hundred years ago our lifespans would be undreamed up, we're living roughly twice as long as your average medieval peasant. But it is still too short! I'm skeptical we'll ever have enough, given that we also live in the most affluent society in all of history yet we complain about not having enough.