Whiteboard. Chalk just doesn't small as good as those scented dry-erase markers!
Blackboards are very messy, dusty, and when photographed are not as easy to insert into a presentation or paper. The black background looks very odd... Blackboards are also quite heavy compared to a whiteboard. Try setting one of those up in your pits.
Art, feel free to bring a blackboard to our meetings, but you'll probably be the only one writing on it.
BEN