Actually WAV's are better quality than MP3's 
My 060 is powerful enough to make a decent stab at playing MP3's by I still prefer use WAV files with mine.
Of course they are! But then it sounds like he is converting MP3 to WAV, and you'd lose the quality, since usually you take WAV -> MP3 (quality loss) and then -> WAV would mean you have the large file size, but compression 'artifacts', lowering the quality.
FLAC is supposed to be a lossless codec, but I'm not sure how much extra CPU is required. Same with Ogg. Personally, I put in that old fashioned shiny disc thing and listen that way, if I want to hear Music from the Amiga that isn't the awesome Mods.

Now if only we could slap a DSP in the Amiga. That's one thing Atari did right with the Falcon, and why it can play MP3s by default (at least from what I've read, I don't have a Falcon, but wouldn't mind one... anyone want to donate?

)
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