Most teaching professionals feel the grip is the most important fundamental in golf. I have two reasons for disagreeing with this classic belief.
First, in the short game -- what I consider the most important part of golf -- the grip shouldn't be your main concern. My testing shows that when it comes to influencing success around the green, the grip falls behind alignment, ball position, and stability. As further evidence of the grip's priority, look at a player like Paul Azinger, who has a great short game but a most unusual way of holding the club.
Second, I disagree because no one grip is right for all the different "games" of golf. If you really want to excel, you would have distinct grips for the power game, the short game, and the putting game.
For the power game -- driving, long irons, and all other full-swing shots -- most golfers should take a strong grip, with the Vs formed by the thumb and forefinger of both hands pointing between the chin and right shoulder (for right-handed players). From this starting position, the hands and forearms have a better chance of releasing through impact, returning to the square position (with the back of the left hand perpendicular to the target line) and turning the clubface over to produce a draw, a little extra power, and extra yardage.
In the short game, extra distance and a draw are the last things you want. From inside 100 yards, you should be trying to hit the ball precise distances on as straight a line as you can create. That means keeping the small, power-producing muscles of the hands and wrists quiet.
The grip I recommend for all finesse shots -- chips, pitches, distance wedges, and sand play -- begins with the hands in the square position, and both Vs aimed at the center or left side (nearer the target) of the chin; most people would call this a fairly weak grip. This is also the position the hands should be in at impact, with only a nice smooth release demanded by the natural swing action (no rapid rolling over) as the ball is struck. If you can keep the hands quiet this way, the clubface will reach impact in the same position every time, which breeds consistency -- a necessity in the short game.
The grip for putting is similar to that for the short game, in that the hands must remain quiet and in a square position, which means they are both parallel to each other and to the clubface. Overlap, interlock, left-hand low -- exactly how you grasp the club is not as important as making sure that the hands mirror the position of the face.
These players prove a point: A big reason why the better ball-strikers were poor putters was their grip. They used a strong grip that was necessary for the full swing, but created problems -- notably too much power and inconsistency -- in the short game and putting. As for the putters and short-gamers, not one has ever been accused of being an especially long or accurate driver.
So should you switch from two grips (putting and everything else) to three (power, short game, putting)? If you've been playing golf for a long time, you might have trouble: You'll need a lot of practice time to get comfortable with a new finesse grip. If you do decide to make a change, be prepared to put in many long hours of work and play many shots under pressure before it feels right. But if you want to play your absolute best, why not?