Another microphone technique that many pianists are fond of using is two microphones pointed directly at each other. Having one mic over the high "C" note and the other microphone over the low "A", will give you a recording that sounds almost the same as what the piano player hears. Experiment with how high you have the microphones setup.
I also did some experiementing and setup the mics on either side of the player about 1 foot above their head pointing down at the piano. Check out the pics of this technique.