All that you would accomplish by suing in state court is to waste a few thousand dollars securing an uncollectable judgment that neither the federal courts nor

All that you would accomplish by suing in state court is to waste a few thousand dollars securing an uncollectable judgment that neither the federal courts nor the Japanese courts will enforce. If Mt. Gox doesn't have the minimal contacts (to the U.S. economy/legal system) necessary for federal court jurisdiction, you're SOL unless you are willing to sue in Japan.