Agree with traditional low post centers. Duncan might be the last of a dying breed.
There are some young players with potential to be good centers, like Brook Lopez and Bynum and Oden, but none of them look like guys who will end up being all time greats. Dwight Howard is the best center in the league and has an extremely back-to-the-basket post game. Al Jefferson and Chris Kaman and Andrew Bogut might be the next best low post scoring centers after Duncan but their overall games have a lot of limitations and none of those guys look like all time greats either. There's some hope with Brook Lopez and maybe even the rookie-to-be DeMarcus Cousins, but it's far from a certainty that they will be great centers either. The league might be at an all time low in terms of having great centers.