Re: Per person
The 1955 defense budget, if corrected for inflation, would come to $356 billion. Given that the 2011 defense budget is about $768 billion, it's essentially doubled since that time. A lot less than a factor of six.
Still, it's worth pointing out that like any other government program, the DoD will basically spend all the money it can get its hands on, and efficiency and effectiveness have historically ranked quite a bit lower in priority than funneling cash into the districts of powerful politicians. Same for NASA, come to that.