My iTunes content is on an external (USB) drive and I want to move it to a larger drive (Firewire). I've copied the content to the new drive and changed the media location in iTunes. The mobile applications and most movies are found, while some movies are not. Most music has not come accross (only 5 out of about 300 albumns).

Before I manually rebuild the library, are there any tips out there as to how the media linking works and if there is something I can do to make this more consistent in the future?