It's a little late but here are my thoughts on the matter. I agree that if a bear is habituated to fire=food it will attract them, but if they have this equation in there head they probably learned first that campsite=food, people=food, garbage=food. So a fire wouldn't necessarily attract a habituated bear, it would probably come to the campsite anyway.
I fight fires in northern Alberta and bears don't seem to be as afraid of fire as most animals, often they will be patrolling a big fires edge, if the fire isn't active, that has pushed them out of their territory while other animals have been long gone. It doesn't take them long to figure out that the fire camps and fire fighters equal food either.
I would say a fire would do more good than anything else because if you burn alot of your garbage there will be less ordours around the camp. A habituated bear in the area will probably stop by the campsite on his territorial travels but probably just walk through if the site is clean and odor free.
Basically I think fires have little to do with attracting or detering bears.It sure took me a long time to get that out.<img src=icon_smile_big.gif border=0 align=middle>