Actually, implements are not required to activate implement powers for any of the implement-wielding classes, so non-magical implements are effectively flavor. Granted, you probably won't have a non-magical implement for very long; it's likely that you'll get a magical one pretty soon in your career, considering the treasure rewards guidelines. The one exception to this is the wizard, who can choose an implement mastery for the wand, staff, or orb. In order to gain the benefit of implement mastery, the wizard needs to cast the spell using his chosen implement, even if it's non-magical.