Which should I use, (native) FLAC or Ogg FLAC?
The short answer right now is probably “native FLAC”. If all you are doing is compressing audio to be played back later, native FLAC will do everything you need, is more widely supported, and will yield smaller files. If you plan to edit the compressed audio, or want to multiplex the audio with video later in an Ogg container, Ogg FLAC is a better choice.