Actor. You can have a career for as long as you want (or are in demand). Most music groups, no matter their success or popularity have a 10 year window (most, not all). Sure, they can play fairs, festivals, etc....but unless they are a legendary group (Fleetwood Mac, Eagles, James Taylor, etc - bands that are currently touring) their music isn't in demand anymore (and therefore their popularity wanes).
Politician, no way in hell.
Athlete would be cool in your prime...but unless you are a HOF type player once your playing days are over, there's not much out there for you except being an analyst or a coach. It would be a fun ride though while you're in the prime of your career.
If you were a successful athlete, what sport would you prefer?
Baseball is on the road all year.
Football is brutal physically, plus the pay isn't what most star baseball players make (minus a few).
Hockey, NBA?