I use Plex on Fire TV to stream my music library. Fire TV is input to Bel Canto C5i digital integrated amp which has awesome sound quality. I use Plex on Iphone, ipad and desktop browser to control it remotely. Plex also does photos and video. You can play photo montages simultaneously while streaming music which my entire family enjoys.
I am not aware of any way to use Fire TV itself without some kind of video display device attached though. My Fire TV is attached to 50" Pioneer Plasma TV via hdmi for video as well as the C5i via Toslink for audio.
