FPSC is a Drag and drop game maker, DBPro is a programming language. There really isn't much to compare. The answers to all your questions are pretty obvious. Since you say that you have used other programming languages before, the difference should be pretty clear
Quote: "What would DBpro give me that I couldn't do already with FPSC?"
FPSC is a drag and drop game maker aimed at creating FPS games, DBPro is a programming language. That says it all really
Quote: "What do I need to make a game with DBpro (.x files, .fx, etc,etc..?"
Well, again. DBPro is a programming language. So it would all depend on what you wanted to create with it.