that burr brown PCM1690 is, IMO, already a top notch chip. so unless you're going to use a really high end dedicated external DAC i'd say just use the AVR as it is. but if i were to feed it to an analog stereo amp, then that would be a different story
but ofcourse kung saan ka mas enjoy yun naman ang importante. right now kasi, mas praktikal na lang ako sa buhay