Baz, you're a lucky guy, movie star smile there.
A930, I know what you mean. If there is really something wrong with your teeth/smile, (like the dead teeth you refer to), it can make a world of difference in your confidence to fix it. I believe that it can actually change someone's personality for the better because they are more likely to be smiling and feel self confident.
My dad told me about how when he was young and broke, (and his teeth were messed up), he never smiled in photographs. It was more like a smirk. Once he could afford to get better dentures/bridges, he smiled anytime he felt the inclination. Decent looking teeth are essential, I just think that anything unnatural, such as over-whitened teeth, looks like schit.