Replace Door, Storm Door, or just add weather stripping?
 

I currently have an old wood door with a screen door that provides no
break against the wind. I put a towel at the bottom of the door this
weekend and I could see it flapping in the breeze. It was a cold and
windy weekend and it has motivated me to do something about this.
There are 3 options I am considering.

1) Get a new fiberglass door and do not have a storm door. I read the
fiberglass doors are so energy efficient the extra cost of a storm door
is not worth it.

2) Add weather stripping to the door.

3) Add a storm door and weather stripping.

Any suggestions? Pros and Cons?