I can't believe i'm saying this, but: I agree with 3run. (oh my god the pain!)

Far Cry and Crisis really have no immersive storyline whatsoever. The environment might be gorgeous, but that really is about it. The day after I finished Crysis I forgot what it is about, and still do to this day.

The storyline of (sorry for taking an RPG) Gothic on the other hand stays with me in every detail til' today. Like a memory I have lived. That is what makes a good storyline, it stays in the players mind after playing the game and it is fun to remember or to play it again and discover some new detail to it, listening to a conversation in the beginning and then applying your previous background knowledge to see how some stuff can be ambigous, and so on.

Bottomline: If you remember the storyline of a game one year later, it's good. Otherwise it's just mediocre or worse.