There are plenty of tavernas in Plakias, all of which serve much the same menu, and several bars but only one disco. This is close to the harbour and is quite noisy at night but, as it's the only one, it's easy to get away from. If you don't like noise at night I suggest you take a room away from the harbour and the main road which runs the length of the front.
None of the other bars is noisy though several of them show Sky sports.