Plexamp all the way, easily the sexiest music player I've found so far. All my music is FLAC pulled from Deezer, and since I've got a very large list of artists tracked, it's super easy to discover new music with the radio and sonic analysis features. It's also got a last.fm integration, which gives me more data than Spotify would about my listening habits.
The only feature I'm really missing in it is collaborative playlists. I can share playlists out to anyone on my Plex server, but they can't add or remove songs.