First, let me start off by saying that I did interviews at the last company for which I worked. The letter you posted sounds like you are trying a little too hard. They will see that as a ploy to take their attention away from something else. Even if there is nothing else, that is how it might appear. If you want a REALLY good reference book, there is a thin book called "sixty seconds and you're hired." It's cheap and breaks down HR questions and tells you why they are asking that question and what they are looking for in your answers. Don't come across as having "canned" answers. Just like the other guys have mentioned: personality, personality, personality. You are qualified for the position, otherwise you wouldn't have an interview. Now they just want to see if you will make it through the program and if they can spend 4 days with you. If you have any questions, pm me.