Although there are many options available in the market today for smart media playback, including Google Chromecast, Apple TV, Amazon Fire TV etc, and they all offer a good solution out of the box to a certain degree, but if you are really looking for an extraordinary solution, you have to look beyond these devices.
Specifically, you have to check out Kodi.
Kodi is an open source multi platform solution for playing and managing smart media, including Movies, TV Shows, Home Videos, Music Videos, Audio Files, Images and Emulated Games. Since it is an open source platform, it has a vast ecosystem and people have created hundreds and thousands of apps, which offer various functionalities, such as controlling or displaying your torrents (on same or a different system), facebook updates, pause movies when phone call received, controlling other smart appliances in your home etc etc. And you can develop more yourself.
So Kodi is a system and then some.
Kodi can be installed as an application on top of Windows, Mac, Linux, Android, and iOS (jail broken) devices.
It can also be installed as a stand alone media device, so your experience will be that of a Blu-ray or DVD player. The new Android TVs from Sony etc allow Kodi to be installed, so this is another added bonus.
User Interface
The biggest draw of the Kodi application is its superb and easy to use interface. Kodi was designed from ground up for the 10-feet experience. The 10-feet experience dictates the display user interface (UI) to be customised for use from as the name suggests 10 feet or 3 meters away.
A 10 feet UI is designed with larger and easy to follow icons, usually clickable or scrollable, rather than mouse interface of the modern PCs.
Not only that, Kodi also allows skins, and boy, are there any skins.... There is a big choice of skins available in Kodi ecosystem, and it is usually a matter of seconds to change skins.
I have shared screenshots of the UI in this post.
Database
The best feature of the media management in Kodi is media scrapping. What media scraping does is gather various information about the Movies, TV Shows or Music from freely available databases on the Internet (think IMDB, TVDB, etc). It then downloads beautiful movie art (banners, posters, DVD cases etc), movie or episode synopsis, cast, ratings etc.
The information gathered is then presented in a user friendly manner.
Playback
Since Kodi is an open source system and actively being updated, there are very few codecs that it cant play today. The latest video codecs H.264, H.265 are fully playable, so are the containers MKV, AVI, MP4, XVID etc. In Audio, FLACs, WAV, MP3 etc are just as easily playable.
Apps
No ecosystem is complete these days without Apps. Kodi has had an App system since very long time.
Installation
Kodi can be installed on a personal Windows PC and connected to a TV screen using HDMI, or installed on a dedicated tiny PC and connected to a TV. It can be controlled using a USB Keyboard, free Mobile App (Android, iOS) and even using a normal IR remote (Flirc, Logitech Harmony etc).
Media
The media can be browsed and played back from the internal hard disk of the same box (as many users do), or even be as elaborate as file servers on a different server on the network.
Multi Room
Kodi allows through use of user apps, excellent multi room functionality. What you pause on one TV, can be picked up and played from the same location on another TV in your home.
Live TV
Another feature of Kodi is allowing plugging in TV capture cards to playback, record and control Live TV feeds. Any TV feed being streamed online can also be played in the system.