D80, D90, D300s and now my new D7000 (less than a week now). I would never do without them. The time and not worrying about battery life over multiple days is awesome.
Yes it is a bit awkward with the D300s and the D7000 with one battery in the camera and one in the grip. They should allow the USB connection and Nikon software the ability to charge the batteries while still in the camera instead of having to removing them from the camera. It would be nice to just plug the camera in every night en walk away. But then Nikon wouldn't get extra money from buying a second charger base.
But the D7000 grip MB-D11 is easier to remove and replace than previous grips.
My only complain is that when you do remove the grip, you need 2 separate covers for the contact points on the D300s and 1 for the D7000. The problem is these tiny covers are small, easy to misplace and you would not want to go out shooting without them.