There is nothing better at a wedding or any other event than a dance floor full of guests dancing.
One mistake I see often is the venue having the bar in another room outside of the reception. People are going to drink and they will inevitably spend a good amount of time floating around the bar. If the bar is in another room the dance floor will be a little empty and you don't want that.
Keep it close so that those getting a drink can see everyone having a good time and will come to dance in between drinks.