Kevin; AAC is a newer compression that is better than MP3. Smaller and more detail. MP3 is a compressed file to facilitate use on the internet or maximize storage on your disks. AIFF is the same format as on your CDs. If you are getting music for the first time (say off your records) to put on CD record it in AIFF format at 44100 hz . Exactly what a CD format is, thus there are no changes from your recording as it goes to CD - one generation only. After you have music on CD in AIFF then delete it from itunes and re-import it as an AAC file to get the benefit of the compression. jj On Sunday, January 4, 2004, at 08:14 AM, Power Macintosh G4 List wrote: > New to list and G4's > > I just got my G4/400 about two weeks ago. I installed Jaguar > on it last night. It sure is beautiful. I have spent this evening > playing around with it and setting up my preferences. One question I > have so far...What are the different music formats in iTunes? There > is AAC, AIFF, and MP3. What are the differences? Is one better than > the other? Which should I use for ripping CD's? > > > Thanks, > > Kevin