I was looking for a good address book and didn’t really come across anything, especially for the PC. Searching more what I did find was the Apple Address Book and the vCard standard for the MAC and very simple Address book for the PC. From there the only good program I seemed to find was A-Book which seems really nice though it is $30 for the full version and the trial is a timed 30 day trial. The vCard wikipedia post was lacking in much information as well.
I found a Mozilla project for a vCard extension but it seems to have been mostly abandoned. I think it would be a great extension to run right along side the Mozilla Calendar extension (as well as the standalone sunbird).
With iCalendar starting to do some really interesting things on the internet with the ability to subscribe and publish online and hReview looking to do some cool things in the near future I really want something to happen with vCard.