Some Linux Distros for the RPi2: Rune, Pi MusicBox, MoOde, Volumio, Archphile. Max2Play, PiCorePlayer.
I tried MoOde first because it is easy to set up and it sounds pretty good with my Schiit Modi usb dac. I'm listening to NPR All Songs 24/7 stream right now.
First learned about it at...