When setting iTunes settings what are the best possible for the advanced importing settings??

If you are only going to be using the songs in Itunes and the Ipod choose ACC most find that it has better quality at a lower bitrate than MP3. Use MP3 if you want to be able to easily move your music to other programs and devices other than an Ipod. For ACC most use the default 128 kilobits but play around with it you may want it higher if you really think there is a difference for you use.