Good mediaplayer for mac that plays flac?
clementine-player - A cross-platform music player based on Amarok 1.4 - Google Project Hosting works very well.
You can also play FLAC files in iTunes with flukeformac - Play FLACs in iTunes - Google Project Hosting (though you'll have to make sure you run iTunes in 32-bit mode). This is what I use, and it works great. You just use the utility to import the files into your iTunes collection, and they will work just like regular MP3s from that point on, without any hassle or having to run some service in the background to make it work.