ADDRESS BOOKs DATA FILES
~/Library/Application Support/AddressBook/
ABPerson.skIndex
AddressBook.data
AddressBook.data.beforesave
AddressBook.data.previous
Images
~/Library/Preferences
com.apple.AddressBook.plist
Address Book will exhibit funny behavior if you start messing with its data files. Sometimes it will start up with an error message Data base is corrupted. (I have seen this happen when I move over the four files in Application Support/AddressBook) and sometimes it will launch and immediately quit (I have seen this happen if you delete the four files in AddressBook but leave the AddresssBook folder intact)
The best way is to use the built-in Backup and Restore which will create a single file containing all the data, move the file over, and then Restore from backup (all done in Address Book except for moving the file itself).
If Address Book launches and does not find a AddressBook folder in ~/Application Support and also does not find a plist file in Preferences, it will create both and populate the default data which contains only one record – Apples own address in Cuptertino.