I am using Thunderbird (Free)
http://www.mozilla.com/en-US/thunderbird/
With the following add-ins
Lightnin (also free this adds the calendar to Thunderbird)
http://www.mozilla.org/projects/calendar/
MoreFunctionsForAddressBook (also free this adds categories to the address book)
http://nic-nac-project.de/~kaosmos/morecols-en.html
BirdieSync (Not free this allows Thunderbird to sync through ActiveSync. I think there is a free add-in for Thunderbird.)
http://www.birdiesync.com/home.html
If you do not use birdiesync you will need to search Thunderbird’s web site for ActiveSync add-ins.