What i am using is Aniosoft iTunes transfer, i think it's worthwhile to use a program to transfer your iTunes library from one computer to another one since you requirement that the playlists,ratings should be retained. On the third-party program i would like to recommend Aniosoft iTunes transfer,with which you can not only backup your iTunes library but also in a proper way with the library's internal metadate,playlists,ratings and etc which you required. The backup files of iTunes library could be able to be recovered and restored later to any iTunes(authorized or not) W/out any change and risk in itunes'layout and arangement including its playlists simlpy through synchronizing it to the iTunes whenever needed.So try the Aniosoft iTunes transfer and it'll possibly work out for you.<br />
more details at<br />
http://www.aniosoft.com/fqa/27-solution/58-transfer-libs.html