One of my old supervisors used to shake his head and say "$5.00 head, $5.00 helmet!" He was referring to Harley riders who wore "beanie" helmets that didn't do much more than hold the other ends of the chin straps. While I am not a motorcycle rider myself, I cannot see why some that do ride aren't interested in using the most effective helmet they can buy, especially after investigating a career's worth of motorcycle crashes.
According to PubMed, motorcycle helmet use reduces the incidence of severe head injuries by 50%, regardless of the speed limit. BC saw 72 injured and 15 killed in 2005 motorcycle crashes due to head injury. (The only contributing factor that ranked higher was "whole body.") Maybe a better helmet might have reduced those numbers.
So, unless you are a Sikh who actively practices the religion, has unshorn hair and wears a turban composed of more than 5 or more metres of cloth, you must wear a motorcycle safety helmet when you operate a motorcycle on BC highways.
What is an approved motorcycle safety helmet? That's a good question. The Designation of Motorcycle Helmets Regulation lists a collection of helmets that are considered to fit the requirement. Of course, it is not exhaustive as manufacturers are continually bringing out new models and it is not updated regularly. In fact, it appears that it hasn't changed since 1987.
So, if you're worried about safety, find a helmet that bears a recognized certification such as DOT or Snell. Spend more than the supervisor's $5.00 because your head is worth it.
References:
Motorcycle Safety Helmets - Section 221 MVA
Designation of Motorcycle Helmets Regulation
Motorcycle Safety Helmet Exemption Regulation
Preventive Aspects of Helmet Safety - PubMed
Is My Helmet Legal? (PDF) - BC Coalition of Motorcyclists
Snell Motorcycle Helmet Standards
Motorcycle Safety Helmets - COST 327