1. Does it play FLAC?
2. Does it read ReplayGain tags for MP3/FLAC/WMA/OGG?
3. Does it have a decent EQ? I'd love to know the type (semiparametric, parametric, graphic) and how many bands of EQ there are...
4. Does it display embedded as well as separate (i.e. stored in a JPG file in the same folder as the music) album art?