The grip will have a significant effect on where the racquet is facing during take back, with the more W. grips tending to face more towards the back.
IMO though, the thing to be obsessed about on your take back is getting the racquet in the pat the dog (PTD) position - face of the racquet mostly facing the ground, racquet parallel to the ground and pointing at the side fence, and below the height of the expected contact point. This is the position from where your swing should start. From this position you can rotate you hips and shoulders into the ball, which will pull your arm around and get your hand out in front. The racquet will naturally want to lay back and angle down, (wrist extension and forearm supination) and the face will open up to the ball. At this point pull up and across and the racquet will whip into and over the ball.
Watch Murray: http://www.youtube.com/watch?v=e3Ce65Adz4k
He's really deliberate about getting the racquet facing down and parallel to the ground early in the take back, and then dropping the position until he's at the right height. Then he starts his forward swing and you really see the racquet layback and then whip into the ball.