Apparently there's no ONE best question for he would have asked it but alas he hasn't so there's no such thing.
Best question? Definiately would be "Where do you want me to put all these boxes of free money and naked girls?"
The best question ever asked is the question that is not asked. It is one you answer yourself through research and study. That way you know the background behind your question and the information you obtained, where you obtained it and how you came to the conclusion which is your final answer.
... and the final answer is the one that you are going with at the time of your death. Otherwise it is only your current final answer.
Not sure if where or how should be part of the explanation. What I'll do though is not ask that question to myself so that I can answer it. Is thinking about a question the same as answering it? Aw shit! Sorry. Wtf am I doing? Dammit. Jeezuz this is hard to do.