I agree with all of the above, but alas, we can't get rid of religion that easily. It'd be nice if we could though.
I'm also gonna throw in the fact that if countries are allowed to still exist, there will be one person (Prime Minister, of sorts) reporting to me, and all countries will be equal in my eyes. No more of this 'America is better' shit...
And there would definitely be some tax changes. I will accept no bribes, if you are rich, you will pay MORE than the middle class (imagine that!).
I think my world would actually be kinda boring... I cant think of anything exciting right now. But then, like Sprouts said, I'm tired. However, I would enjoy using my power to litter chests all around the world in hidden locations, so that when a person finds the chest, they may open it up and find that it contains some Dayquil (Elixer) or other goodies. Just to see who finds what.
Jam it back in, in the dark.