In each of our three ballrooms, we have two areas where the dance floor and entertainment can be placed. There are positives to both locations.
The most popular location is in the center of the ballroom. I typically see this when the entertainment is a DJ, and when the dinner is plated. Placing the dance floor in the center makes this the focal point of the ballroom, and everyone is equal distance away from big events. When you are performing your first dance, cutting the cake, and giving toasts- everyone can see the happy couple in the middle.
The other dance floor location is at one end of the ballroom. I typically see this set up when the entertainment is a band, and when the dinner is station style. When you have a band, they usually require a large stage, and you do not want the stage to cut the ballroom in half, if you put them in the middle. The dinner is usually station style because it promotes the guests to move around, and there is a designated dancing area and dinner area. This is also a popular location if you feel not every guest will partake in dancing. They can sit farther away from the dance floor, and hold a conversation.