A common misconception that occurs with younger athletes is that having big biceps equals more power in sports. This is far from the truth as most sports require pushing motions which rely heavily on the triceps. The forearms are also instrumental in any sport that requires gripping any piece of equipment. This is not to say the biceps do not matter as they surely do, just not as much as most think.
There are no specific arm exercises that are any more important than the others. They should all be given their due attention. Below are the 3 designated categories for the arm's muscle groups: