If I where as rich as some of those in that list I would give most of it away. I'm sure I would enjoy being so wealthy, but there is little you can do with 40 billion that you cannot do with 1 billion.

If I had 40 billion I would definitely give away 39 billion. I know some say that money corrupts and makes people greedy, and they then do not want to give money away, believe that if you like, but I know that I would give it away if I had it.