Address Book Recommendations?

I recently started using Thunderbird as an email client, and while I like its interface, I'm not happy with its address book. In particular, you can only save two email addresses per person (I have five right now, and many of my students have three or four), its tabbed display forces me to do a lot of extra clicking when entering information, and there doesn't seem to be a "show new entries" capability. I'm therefore looking for a better address book application. It has to integrate with Thunderbird, and must not store addresses on a web site. (I currently keep my address book in LDIF format under version control, so that I can keep the three machines I use regularly in sync.) Any suggestions?