What is the best contact management software?

Examples include TeleMagic (Windows), ACT! (Windows), Maximizer (Windows), GoldMine (Windows), Entourage (Mac OS X) and Contactizer (Mac OS X). The market for contact management software has weakened since the late 1990s, when Microsoft integrated basic contact management features into its Outlook email and PIM program. Even on the Macintosh platform, Apple began including PIM, calendar, and to-do applications with its operating system in 2002. Many developers of contact managers have consequently gone out of business or been taken over by other companies.