If you have to take one from my portfolio, this is it. It's all international energy companies. All top flight, chosen because of strong dividends. This one will hedge against a number of issues you may be worried about.

With Brazil cutting down the Amazon to grow sugar cane, they are pumping out a lot of ethanol. They've also forced cars and such to run ethanol. Relative to most countries, they'll do well after peak oil.

Gotta love gold bullion in tough times as well. It may be expensive, but it is a great hedge.

After peak, everyone will be pumping and drilling and such. The big U.S. oil services companies will do well. This Profunds fund, "Seeks daily investment results, before fees and expenses, that correspond to 150%, of the daily performance of the Dow Jones U.S. Oil Equipment, Services & Distribution Index." Should do well.