PureMusic Player also plays FLAC files, but I prefer to convert them to AIFF using xAct.
I can't remember exactly which, but one of xAct or PureMusic requires that the FLAC binaries are already installed. MacFLAC will install the binaries (and then you can delete the application itself).
xAct is fantastic. It actually comes with the FLAC codecs (right word?) because I downloaded it yesterday. I've used it many times before and from memory, it even comes with the APE decoders too. It's a very versatile app.