I agree with DS, but there are some people who believe that since Charge is not written like a power the movement portion has no target and you don't choose a target till you make the attack. To me, that makes no sense because how else are you suppose to know how to move directly toward something unless you choose a target first.
It also starts to get complicated if you allow the charger to change targets mid charge. Lets say that say that as the charger is running past the Fighter the Fighter make an OA, but not in the first square that was available. He instead makes an OA in the second adjacent square the charger runs through and hits and stops the chargers movement. Would you still allow the charger attack the fighter even though he is not in the nearest square from his starting position from which he could have attacked the fighter?