Cobook

Cobook Contacts is an intuitive, engaging address book.

Solve the problem of contact management with Cobook Contacts and its simple interface and powerful syncing and integration possibilities.

Keep your contacts:

• Organized with tags. A simple tagging system means finding particular contacts is as easy as can be.
• Automatically up-to-date. Keep your contacts up-to-date by syncing them with Facebook, Twitter, or Xing profiles.
• Within reach. Quickly access your contacts from the menu bar on your Mac or on your iPhone or iPad with the iOS companion app.

Note: Cobook is free to download, but contains several in-app purchases which significantly extend its functionality, so we've listed it as a demo.