Awesome. I never bothered with AAC before because converting to AAC took forever in comparison to MP3, but with iTunes 4 I swear it's now just as fast or faster than converting to MP3. I could always tell the difference in quality and now will take advantage of it. It takes only a minute or two to convert each CD from directly in iTunes... another example of fine Apple Software. Not sure if I will use the store or not, but it looks pretty sweet and easy to use. Excellent update!