P.S. Before installing it is worth selecting all your address book entries and "Export vcard". Comparing the 10.3 vs 10.4 "~/Library/ Application Support/AddressBook" directories reveals some different file naming protocols. Updating the new address book was not a simple case of copying over 10.3 files to this location (although to be honest, I avoided renaming my 10.3 files to those of 10.4. I was unsure whether new archiving methods are in place for 10.4 databases, given the advent of Spotlight). Importing vcards was the method I had to choose to update my address book, so ensuring your old address book is archived in this format prior to 10.4 installation might be a handy tip.

I should also add I performed a clean install. Such problems may not exist doing an upgrade installation.

Cheers, Matt