I was just reading up on the Canadian National Parks website about what they recommend for black bears
They recommend suspending food between 2 trees and recommend bear proof containers only when you're somewhere that you can't hang your food. I wouldn't have thought about that one but the picture on this related page makes it clear that just hanging might not be enough for some bears:
http://www.pc.gc.ca/docs/v-g/oursnoir-blackbear/page4_E.aspThey also recommend a 100M distance between camp and smelly activities like cooking.
http://www.pc.gc.ca/docs/v-g/oursnoir-blackbear/page6_E.asp