DAMN, I'm so happy I wear a seatbelt every day... a seatbelt saved my life in a head on colision almost 10 years ago, cop at the scene said I would have flown a good 60 feet right through the windshield..
While I do promote seat belts, I think they can be flawed too. There have been many people that the seat belt comes unlatched on, when impact occurs. There was a story about it a number of years ago.
In general though, belts are a good thing to invest in while getting in your car. A friend of mine was drunk driving about 3yrs ago, and hit hit a Ford Explorer with his Lexus. The Explorer rolled, and everyone but the 15yr old was wearing seat belts. The 15yr was ejected, the Explorer rolled over him, and two days later they pulled the life support on him and he passed on.