The answer? There is no ‘one’ answer; that’s why I titled the question a paradox. The problem was first described by William Newcomber, which eventually became known as Newcomber’s Paradox.
The Explanation (taken directly from William Newcomber):
_"Let us look first at the argument for taking Box 2. You believe Mr. Toad is an excellent predictor. If you take both boxes, Mr. Toad almost certainly would have anticipated your action and left Box 2 empty. You will get only the $1,000 in Box 1. On the other hand, if you take only Box 2, Mr. Toad, expecting that, most certainly will have placed $1 million in it. Clearly it is to your advantage to take only Box 2.
Convinced? Yes, but say Mr. Toad made his prediction a week ago and then left. Either he put $1 million in Box 2, or he didn’t. If the money is there, it will stay there whatever you choose. It is not going to disappear. It is assumed ‘backward causality’ does not apply; that is, your present actions cannot influence what Mr. Toad did last week. So why not take both boxes and get everything? If Box 2 is filled, you get $1,001,000. If it is empty, you get at least $1,000. If you are foolish as to take only Box 2, you cannot get more than $1 million. There is even a slight possibility of getting nothing. Clearly it is to your advantage to take both boxes!"_
What it really boils down is how much you trust Mr. Toad.
I trust Mr. Toad so I would’ve chosen Box 2 only.
For everyone who answered you’ll all be getting +1 Karma! :-D