Well, weather and HTC seems popular, but my opinion is that this is a phone,a nd the wm phone app is more than awful. I want to be able to one hand/finger get to the right contact and dial their number.
I vote for iContact
http://www.freewarepocketpc.net/get-icontact-v0-3.html. I'm using v0.3 because 0.4 won't let me actually launch the contact details into dialing.
I also think people should take a look at GoodWin
http://www.iwindowsmobile.com/mobile-launcher.html. I really like its iPhone like UI and the FunContact is ok too.
My $.02