Whatever software you use, make sure you use the highest quality settings. What sounds good on your iPod may sound like crap if you play it through a good stereo 3 years from now. Hard drive space is cheap (and getting cheaper). I use MP3 format, 320 kbps, files are around 3-5 meg per song, but I know I'll never have to do it again. And everything plays MP3s, not sure about other formats, especially iTunes M4P (or whatever) format.