One question I see asked all over the place by switchers is how to move an address book from Outlook on Windows to Address Book in OSX. I've seen utilities and scripts out there that claim to do it, but I've never had or heard of much luck with them. If you're in the same boat, a post over at macosxhints.com lays out a down and dirty method using Mozilla's address book and Excel to shuffle all your contacts from Outlook into an LDIF format that OSX's Address Book can import.
Sounds nasty I know, but if you've been having issues like this and have all but given up - this could be your contacts' last hope. If anyone gives this a whirl, (I switched years ago) please feel free to post your experience.