In the latest Newscientist there's an article about our planet's greatest mysteries and the first question is: How come Earth got all the good stuff?
Also, Iintelligent Design asks more or less the same question, so is the strong anthropic principle.

But to all of them, we must answer: we are here because we are here. We're here because the conditions were suitable for us to be here. The "good stuff" of earth is good because it was already there when we evolved from it. It isn't necessarily good by itself. Any other world might have good stuff to something else too, but because it evolved another way, that something is going to be very very different.
Stars are very different; some are extremely energic and some are rather cold. We need an average one but that's because it's us and our sun is an average one. But what could happen around a very violent one?
Another article (french magazine) is about the statistics. Life on earth took place amid an extraordinary number of circumstances. The probability declines so very rapidly it can ever happen again in our own galaxy (or even in the entire universe). If the probability is lower than 10 exponent-12, then we're alone.
Scientists know the physicochemical history that lead to life happened in a totally umpredictable way.