This has been happening to me for close to a week now I think. When I bring up my address book, my PAB is listed in the AB pane 9 or 10 times. It's the same address book (I only have abook.mab in my profile directory) but rdf / mailnews is showing it multiple times in the pane. Paul reports that he sees this on the Mac too so I'm setting the platform to all. I seem to crash a lot when I check on these address books assuming i'm not selecting the first instance of the AB. (i.e. entries 2-8 seem to crash).
fix checked in (libpref\nspref.cpp 3.66)
I just pulled nsPref.cpp and rebuilt. I don't see all the address books anymore. Thanks Candice.
mark verified per scott's comment.