As usual, I was away from home on the fateful morning of Sept. 11. As I was sitting in a Los Angeles hotel room, getting ready to head to the airport for another airplane ride, I turned on CNBC. The tragedy that befell our nation was outside any logical economic scenario, as none of us had taken into account a terrorist attack on New York and Washington. And very few of us will remain unscathed in the aftermath.

As investors, we can expect more price volatility across all financial assets, especially the stock market. Equity segments such as consumer staple stocks with lower relative volatility vis-a-vis the broader equity market should continue to outperform in this type of market. Names like Pepsi and Safeway come to mind.

More than a few of us will worry about short-term liquidity. Mr. Greenspan and the Fed acted quickly to raise liquidity in case of a run on the banking system. This will undoubtedly help to push short-term rates down at the risk of longer-term inflation pressure. Your local bank's savings rates are likely to decline.

It's hard to guess which direction the U.S. dollar will head. The dollar is still a safer bet than most other currencies. However, pushing liquidity into the U.S. banking system will favor a decline in the dollar compared with other currencies. The jury is still out on this one.

Energy remains a key question. Near-term energy futures have risen in expectation of a very forceful U.S. response to the attacks. I expect that international and domestic oil and gas stocks will see better relative price performance compared with the broader market. However, the real question is sustainability.

If energy prices escalate, the global economy will spiral down and push local economies, including the U.S. economy, into recession. Subsequently, as the economy weakens, energy demand would decline, causing weakness in energy prices. Multinational oil companies still make the safest long-term bets, including names like Exxon Mobil and ChevronTexaco.

We all know that the travel industry will be hard hit, as will some of the financial stocks. Hotels, airlines, and other travel-related service companies, such as American Express, will feel the pain the longest. Retail, in my mind, also will suffer as few people will feel like shopping.

We already know that the big winners, near-term, are defense stocks. Enough said.

What about technology? Given near-term business trends, the recent attack will put a further damper on IT investment spending. However, certain segments should thrive. The disaster-recovery business should see increased interest. Companies such as Comdisco, IBM, and SunGard Data Systems will benefit. As an investor, however, make sure you account for the rest of their business when evaluating future prospects. Only about 25% of SunGard's business is disaster recovery. The rest is investment support services and software. The larger part of its business may come under pressure as resources get reallocated. We may see a further push into data-center outsourcing, primarily to reduce business risk.

Security services and software will remain hot areas. Wireless service and communications-billing software vendors are likely to be rewarded. However, rollout for third-generation wireless services will likely be pushed back. Enterprise application vendors are going to suffer through the year. This will hurt many of the enterprise software companies that rely heavily on end-of-the-quarter selling.

As an investor, the hard part is to not react emotionally to the immediate news. For many of us, the prices already will have adjusted by the time we get around to buying or selling. (I know a few investors who bought defense stocks after they had already spiked upward, assuming they would continue upward, and they lost more than a few dollars.) The bottom line: Plan your portfolio for all seasons.

The best investment we can make is to count on the U.S. economy to recover. That alone will be a testament to the long-term strength of Americans and the capitalist system on which our democracy thrives.

William Schaff is chief investment officer at Bay Isle Financial Corp., which manages the InformationWeek 100 Stock Index. Reach him at bschaff@bayisle.com.