One thing that you have to decide is how dynamic your bread crumb trail is. For example, your site may have a "Product Details" page. The user can get to this page in several ways. Maybe they got to that page via "Product Search" > "Search Results" > "Product Details". Or maybe they got there via "My Account" > "Recent Orders" > "Order 30393" > "Product Details".
The project that I am on has a fairly static "bread crumb" such that when you are on a particular page you will always see the same trail ( "You are here: Home > Products > Product Details"). This is done by a configuration file that generates the trail based on the name of the action.