Well, like I said, the only way
not to lose the ratings (and play counts) when you're moving the files to another drive is to have that drive mount at /Users/
yourusername/Music (or add /iTunes after that, if you don't want to replace the whole Music folder). If you happen to have your music at some other location (i.e. you don't have iTunes manage it for you), just mount the drive at that location.
When you do that, iTunes sees the files in the same place, so even though they all now have different file IDs, iTunes guesses that they're still the same files and uses the old file rather than making a new one.
'Course, this all has to be done
before you launch iTunes after you've moved the music.
To get something to mount where you want it rather than in /Volumes, you can use the
mount command in the terminal, but by far the easiest way is to edit /etc/fstab (note, you'll need to use
sudo to edit it), and make something that looks like this:
Code:
#Device Mount point Type Setting Dump fsck order
LABEL=Swap /private/var/vm ufs auto,rw 1 2
LABEL=Projects /Users/poetman/Projects hfs auto,rw 1 3
LABEL=Music /Users/poetman/Music hfs auto,rw 1 4
Whenever you boot, autodiskmount will automatically mount it wherever you tell it to. You don't even have to reboot if you have it on an externel drive - just unmount the drive, disconnect then reconnect it to get it to mount again.