Gold

So the Wall Street firms tank, and the housing market crashes in response to all these foreclosures coming on the market. So lots'o'companies have difficulties, including those which do business overseas.

So overseas companies start not wanting our dollars, and start buying gold, and surprise, the gold price goes sky-high. Meanwhile interest rates are at zero, so there's no point, really, in putting or keeping money in the bank.

This illustrates why it is always best to keep your assets in sharpened Topiary shears and live in a hedge, or better yet, just BE a hedge.