Why would anyone vote yes to AV?

I just don't get it. What's wrong with the system we have now? 1 person 1 vote. It's not hard to understand. It's the fairest system. All world super powers, have the voting system with one person one vote e.g. America, Russia and so on. They are only 3 countries in the world who have adopted this system Fiji, Australia and Papua New Guinea. And two of the three countries are thinking about ditching it, simply because it's unfair. How can the person with the most votes not win. If you cross that line first, you should be the winner, not the person behind you. The only thing this voting system will do is give parties like the BNP, a better chance of gaining power. Also this system will cost the government �250 million pounds. We should be using that money on more important things like Education and Health Care. I'm a Labour supporter, our leader is saying yes to this disgraceful system, i'm going with the Torys with this one, this system is a disgrace.