Hugh Hefner from that "Playboy: The Mansion" video game that came out a couple of years ago. Reason... I think I'll let you use your imagination for that one. Either that or Moneybags off the Spyro series, he sure knows how to con Spyro.
You want to be an 85 year old man on the verge of a heart attack at any moment? He's old enough to have any and all medical problems you can think of. Not to mention all those wonderful women he's would most likely cause said heart attack from too much excitement. Good luck with your last three years of life. Sorry if that sounded harsh, but wanting to become old doesn't seem like a reasonable move. You'll be there soon enough. How about Leisure Suit Larry instead?
I guess I would want to be... The Apprentice in the Force Unleashed. I want to be a Jedi!
I would be Hugh Hefner "THE VIDEO GAME CHARACTER" in the video game you play as Hugh Hefner in your mid 20's so believe me I've got plenty of life left.