PowerAmp is a good music player for Android devices. You can try it for 15 days.
http/powerampapp.com/
There is also WinAmp, however the free version does not support FLAC and there is not free trial period for the Pro version which does support FLAC. http/www.winamp.com/android
agree that flac might not be natively supported by the stock android music player but is supported by apps.
i've used poweramp... not bad at all but its a paid app. i had it for awhile before i rooted and went to miui... the stock miui player is more than enough for me.
if you want to try winamp.. just try it with mp3 files first to see if you like the interface.
People use FLAC over WAV or MP3 for two very important reasons.
1. FLAC a lossless codec and does not make music sound like crap which is what MP3 does. MP3 like many other countless audio codecs out there are lossy codecs.
2. FLAC is smaller than WAV files which allows you to basically store about 2x more FLAC files than WAV files on a SD card.