If you don't know what kind of shaft is right for you, go to a pro shop and get fitted.  The shaft makes a huge difference in the club you use.  You can have two drivers with the exact same club head, but two difference shafts.  The ball flights will be different and can change your game.

I will leave it up to you to learn what is correct for you, but here are some basic info on shafts:

Graphite shafts are lighter, which will increase your swing speed, and this can increase your distance.

Low Kick shaft - helps get the ball in the air quicker

Mid Kick shaft - helps produce a ball flight not as high as the low kick

High Kick shaft - helps give you a lower more boring ball flight.  Typically for the better golfers.

Each person has a different swing.  What works for one person does not mean it will work for others.  There are other options when looking into shafts, and that is the shaft having a soft tip or stiff tip.  Again, go get fitted for the best results. 

The wrong shaft can mean 20 or more less yards.  It can also mean the difference in hitting the right side of the fairway versus the middle.  If you find you typically hit the right side of the fairway, that means your shaft could be too stiff.  The simple change from stiff to regular can effect what side of the fairway your typical drive lands.