There are two kinds of tripod heads: ball heads and pan heads. The ball head is simplest and provides a full range of movement for your camera. If you tend to shoot quickly or at moving objects you will like a ball head. With pan heads you have multiple locking levers that adjust the pan in different planes of movement to allow you to move the camera on the tripod. Pan heads are quite useful for panoramic shots. The trade-off is speed, it takes more time to unlock and adjust the levers than with a ball head.