It is important to mention again (it was somewhat buried up-thread) ... it is not illegal to carry amounts over $10,000 with you. It's just that you have to report it. And it does not just apply to cash ... I beleive the customs forms asks about "any instruments," which would include checks, traveler's checks, etc.

I once asked CBP about the requirement out of curiosity -- not that I ever have held that much cash as once.