I use Dropbox, Spotify and bunch of other tools, but this seems interesting. Especially Rocket Chat.
It's easier than ever to spin up a server and do your own computing. Keeping your data on a system you control means you don't need to worry about services shutting down, nefarious Terms of Service changes, or who might have access to your information.
You might reasonably decide to stick with hosted software for the convenience it offers — but you should be aware of these free alternatives to the biggest services:
OwnCloud is a great replacement for Dropbox, Google Drive or Microsoft's OneDrive. It has a slick web interface, desktop sync clients for Linux, Windows and OS X, and mobile clients for Android and iOS.
Tiny Tiny RSS
Google Reader's untimely demise spawned two popular feed aggregators, Feedly and Feedbin. Tiny Tiny RSS is a fantastic alternative. It supports content filtering, podcast aggregation, plugins, theming, and social media sharing. It's primarily a web app, but it also has an official Android client.
This blog runs on Ghost. Ghost.org offers a hosted version, but you can also download it here and self-host. Ghost provides a great writing experience — and unlike Medium, Svbtle and Blogger, you have complete control over your data.
GitLab is great for self-hosting both public and private Git projects. It has a robust permission system, supports merge requests, works well with continuous integration servers, and includes a per-project wiki and issue tracker. It's not as social as GitHub, but it's just as powerful. Tiny Tiny RSS (above) is hosted on GitLab.
RocketChat is a polished, extensible Slack alternative. It supports video and audio conferencing (which Slack lacks), link previews and file sharing, and has native clients for Windows, OS X, Linux, Android and iOS.
Ampache is a simple web-based audio and video streaming server. Ampache could make a good alternative to Rdio, Spotify or iTunes Music, or you could use ownCloud to synchronise your music between systems.