If I was immortal, I'd first work at building enough secure wealth to maintain myself perpetually. This would be pretty damn easy once over a critical point, which is only a matter of time.
After that I think I would travel a lot. At first casually, tourist style, but then increasingly motivated to go everywhere and do everything. It would be a never-ending task. Humanity produces far too much stuff for a single person to keep up on it all. Heck, people alone. More people are born than one person can ever get to know.
I think it far more likely that disease, violence, or some other factor outside my control would ultimately end me before I felt a desire to end myself. Even if I reached that point, I would rather go the route of increasingly tempting fate to kill me rather directly offing myself.
Well..let's say that what I plan on doing today for my future may be the exact opposite of what I am inspired to do tomorrow for my future..my life is a book being written as I inch along, and possibilities are completely endless. I wouldn't like to live forever, though..I'd get too bored with this world. I don't think I'd want to live much past 85.
Is it that by its indefiniteness it shadows forth the heartless voids and immensities of the universe, and thus stabs us from behind with the thought of annihilation, when beholding the white depths of the milky way?