Suppose I sync a few *selected* albums or artists in my library and then after that, sync the *entire library*... does iTunes know to NOT transfer the songs/albums that are already synced (already on the iPod) or does it transfer everything? In other words, when choosing "Sync entire music library" does it do a 'compare libraries' routine before blindly transferring everything? I will find out soon enough... I did a sync by selecting all the *Artists* boxes but I think it's skipping a bunch of tracks because some of them are compilations. When it's finished (in a few hours*) I want to sync it again by choosing 'sync entire library' and I'm hoping it won't re-copy the 702 songs that will be on there once this first sync is done! *why so long? ...because I'm using full res 44.1 / 16 bit WAVs and I have about 80 albums transferring over USB 1.0!