OSMC

Raspbmc is an XBMC and linux-based OS distribution for Raspberry Pi, created and maintained by Sam Nazarko.

Main features

Custom Linux distribution with minimalised kernel.
Auto-updating
UI installers for Windows, Linux and Mac OS X to allow installation onto a removable device
PVR / AirTunes / AirPlay / Spotify integration
Same stability and support as the Crystalbuntu Linux distribution
Expansive capabilities allowing the installation of a desktop and web browser
AFP, NFS and SMB file sharing
Configuration utility allowing installation of custom nightlies, audio configuration, update management,
Server mode – allows MySQL database hosting and Thumbnail sharing for XBMC multiseat systems.
1080p decoding
Free!