What does the term it's the 64.000 question mean?

Answer 1

The 64,000 dollar question is the big question or the main question. eg whether to vote for Obama or McLean is the 64000 dollar question right now. The phrase comes from a television quiz program of that name where the prize for each correct answer increased from 100 to 200 etc right up to 64000 dollars. That last question was the hardest and obviously the most important.