Being left handed in a right handed world forces you to adapt and become something even better. By being exposed to so many right handed obstacles, lefties become more ambidextrous and fluid with both hands. I also noticed a lot of left handed people I know seem to think outside the box and have multiple talents. And a lefty will usually have an advantage in boxing or other sports, due to the different angle, which looks odd to right handers. I think lefties are truly one of a kind people.
Left hand is definitely better because of many reasons: 1.Lefties learn sooner or later to also use right hand and that makes them more intelligent because of the brain work it takes. 2. Lefties learn from the first years of life what it means to be "diferent", they have to face problems and critics from others and they learn to defend who they are, so it helps to develop your personality and social habilities.
Right handed ... only because many things are already made to be used in the right hand. Being left handed would be an inconvenience.
More equipment is designed to help right handed over left handed people. Also, being right handed, I'm slightly biased.
I'm left-handed but most people aren't, so it is a lot more useful to the human race. Not really sure what would make the left hand more special...