I use .ogg files in preferance to mp3. I've done a lot of listenieng with my big Carver system and speakers and have come to the conclusion that .ogg is better than mp3 files (when comparing at the same bit rate). The only thing is that if you use portible players, you would need to dump iPod and go to iRiver (or something). I rip CDs using cDex (free) and it comes with some codecs including Ogg Vorbus (.ogg). Generally I am happy with bit rates of 160 or greater. I have also downloaded 2 variations of the ACC codec and quite like it too. It is the new mp3 replacement and iPod can see it. Some ACC codecs can come preset to 15K max frequency and others you can change. Hope this is helpful. Finally, I wish more people used .ogg.