Seat belts have saved my life twice already. Been hit by semi-tractor trailers twice now, once head-on, once driver's side door. Head-on I was uninjured, but the side impact, in my little 1985 Honda CRX two seater....well, let's just say that it hurt, and I don't recommend it. Still have metal in me from that one.
Wear your seat belts people! It's worth the trip into Santa arse.