falconsgyre said:
"I love you."
Spoken with feeling, to someone important.
Though it would suck if they weren't there (which could be likely if you have never told them before).
OT: I'll have to go with this guy's(/girl's?). When I die, I want them/him/her to know that they were the most important person in my life. But if there isn't anyone that important in my life when I die, then I'd probably say "I have no regrets", even if I do, I want my death to be as painless as I can make it for those around me, and letting them know that I died without regrets regarding my life seems like a pretty good way to serve that purpose.
EDIT:
Nerdstar said:
Thanks to denial I'm immortal!
I'm too stubborn to die!/To live forever, just try and die, but miss (FYI, you only get one try at this).
Alternatively, "I'd never thought I'd live long enough to die ... whaddya know *dead*"