The length of time I'd like to live if the choice were up to me depends on the quality of that life.
Without some super healing factor that allows the body to always return itself to perfect health, life would become really problematic. As it stands, I already have sources of chronic pain from injuries and from birth, so I wouldn't really want to carry those pains for 500 years or more. That would be lame. But if the body were perfectly healthy and felt good, I could probably amuse myself for at least 500 years.
If the environment were expanded to allow the exploration of other worlds, the time I could amuse myself for would probably increase further.
But eventually I'd ask, "now what?" After a while, things become repetitions of other things with only slight changes.