Discord OR skype Or Teamspeak

Discord is the best.
You can create your own server with chat and voice channel and fully customizable permission setup with bot that makes the server more fun and feels automated and pretty. Also there's so much expansions you can make in discord such as creating your own bot that do what you want to do like fetch forum post using RSS, welcoming someone, adding auction, adding giveway that's automated, adding webhooks and so many more you can do with discord and make you can sit infront of your computer (if you're using PC of course) for hours just to enjoy discord with your friends.