You guys are awesome, though I am still working on glok's answer.

I thought of the negative implications if I wished for no more war, or world peace, (which is kind of the same thing) or that there would never be hunger in this world again. The stock markets all over the world would crash, sending us into a panic and the world would become so over popoulated that it could not support life as we know it and it would affect the delicate balance of nature that even now hangs precariously in the equation of our life.

If I had a fourth wish it would be to find cures for us and all that we suffer from.