Probability Quiz

So a co-worker and I were discussing the fact that it seems like the average person does not have a good grasp on the concepts of probability/statistics. I stumped him with this one. It seems it gets a lot of people. I will post the question today and the answer tomorrow for anyone that feels like playing. It is a classic problem so some people may allready know it.

Question:
Three boxes are on a table. One of them contains $1000. I give you the option of opening one box and keeping it's contents. You pick box number 3. Instead of giving you box 3, I open box 1 and show you that it is empty. Since I am a generous guy, I now give you the option of choosing which of the remaining boxes to open. Is there a better choice? If so which one?

--Chuck