why was the hudson bay area important to the british fur trade?
Because of the cold and lack of people in the Hudson Bay area, it was believed that region had the best fur-bearing animals. The Bay and its many rivers also provided transportation from inland Canada to Europe.
Check these sites for more information.
http://www.canadiana.org/hbc/intro_e.html
http://en.wikipedia.org/wiki/Hudson's_Bay_Company