After experimenting with iTunes, I noticed that after ripping my U2 Joshua Tree CD, the sound had a lot of static when I ripped it into AAC. The sound quality was slightly better, but the static makes the music unbearable, so I had to stick with a slightly less quality MP3.

As far as I know, OOG cannot be played on a 3G iPod. Though I hope software will help, but iTunes does not convert to OOG, so I'm assuming no iPods can play OOG. Though AAC isn't technically Apple(it's Dolby), MS doesn't seem reluctant to support the format because Apple invest so much into it.

Right now, most of my files are unprotected MP3s. Other files are m4p(Apple's encrypted version of MP4) and m4a(apple's unprotected MP4s). The MP4 formats, obviously, sound great. It's the format iTunes uses, and they do allow me to convert to MP3/WAV/AIFF. No OOG, even though I've heard great things about a format that I can't use on my iPod.

I'll probably stick with MP3s, only because MS programs do not support them, but WinAMP does...using a plugin.