CHARTLEY'S PROFILE

I've asked people about this before, and I get different answers all the time. So it usually makes for interesting discussion. The question?

How do you go about planning the story for a game? I'm not really sure what the best way is. Some ways I've heard:
-Planning the whole game out in detail before even starting the game.
-Making a rough outline, and then filling in the specifics as you go. (Is this how most people do it?)
-Write as you go. Maybe plan the next few hours or so, but not the whole game in advance.
-Wing it, just make the game as ideas come to you.

I honestly have no idea of what the best method is, nor have I found a method that works for me yet. Since I have yet to make decent progress on any game I've started.

Your thoughts?