if youre immortal your chance of getting a horrifying disease skyrockets too 100%
Your chance of surviving long enough for a cure to those horrifying diseases also skyrockets too (although maybe not to 100%).
Well, assuming I don't physically age, I would choose myself.
I think it's going to have it's own horrible aspects, being immortal, but I'm afraid I am greedy enough to take away the obvious benefits over giving them to my friends.
My atonement for that is knowing that I will see every person I love die, including those friends.
On the other hand, I could guide my family for generations.