This really shouldn't be so complicated. I don't know why Apple has to make moving files such a huge hassle. Anyway, I have 2 other methods for moving the iTunes library:
The first method, and the best, is to move the entire library to the new drive, then change the new drive to the drive letter of the original drive. So for example if your library is on drive D, change that to E. Then make your new drive D. Change nothing else. Open iTunes and everything will be exaclty the same since the path for the library has not changed. Obviously this will not work if your library is stored on the operating system drive, or you need to consolidate media files from more than one drive, or if you have other files on the old drive that need to retain the same drive path, which brings me to method two.
The second method, which I had to use this time because changing the drive letters would have caused an even bigger mess for some other files, is to first move the entire iTunes library to the new drive (look under preferences - "iTunes media folder location" to see where this folder is located). Then change the "iTunes media folder location" to the folder located on the new drive that you just moved. When you start iTunes and try to open a file, iTunes will ask if you would like to locate it. Locate the file on the new drive and iTunes will ask if you would like to automatically locate other missing files. Almost all of the files were found when I used this method. Some albums still had exclamation marks next to them but were fixed by repeating the same process a few times. Some album artwork was missing but simply selecting "get info" on one track in the album will restore it So now I have all of my music and podcasts moved to the new drive and all of the artwork, playlists, play counts, track info, etc. is still intact.
I don't know if either of these methods will work for everyone since iTunes file orginization can be such a mess. Here's how I have mine setup:
I am running Windows and iTunes creates the "iTunes" folder under C:\Users\me\Music. This is on my operating system drive and contains the "iTunes library.itl" file as well as all the artwork, I believe. All of the media files, however, I keep on another drive which looks like this: F:\My Music\iTunes. So if I want to move my library to a different drive, I move the entire folder labeled "iTunes" on drive F:\.
Hope this helps.