Here's the thing, with big budget movies are typically loads of fun because studios have buried tons and tons of cash into it. However, they typically lack on story and substance.
However. If I had an unlimited budget. I would create a non-cgi, down and dirty tale of a cop/vigilante in Japan. Basically combining Batman Begins with Blade Runner.
Now THAT would be something I would develop. In fact, it kind of is a project I wrote a while ago.
Lets just get that budget.