Energy may be a wild ride for investors, but it could be the vehicle of choice.

Even swooning credit and stock markets can't overshadow $70-a-barrel crude prices or emerging markets that can't seem to consume enough oil. Only a global recession could potentially modify the scenario.

In the quest for more oil and natural gas, the giant drilling companies lead the way.

For example, Diamond Offshore Drilling Inc., with 43 drilling rigs operating in the U.S. and internationally, has seen its stock price soar this year.

Ten of its rigs operate in challenging deep-water environments that receive lucrative contracts.

Sophisticated deep-water drillers Transocean Inc. and GlobalSantaFe Corp. plan to merge by year-end in a cash and stock deal that will create an even more imposing company in the competition for tough international projects.

"There's been a realization that there must be more capital spending to get oil and gas out of the ground because supply can't keep up with global demand," said Stewart Glickman, an analyst who covers oil-field drillers and services for Standard & Poor's Corp. in New York.

"Demand is being driven by emerging markets, and China in particular, with oil and gas supply struggling to keep pace."

Energy stocks are up about 17 percent this year, according to the S&P 500 sector score card.

"Strong oil prices had buoyed energy equities throughout most of 2007 until broader market hysteria kicked in a few weeks ago," said Collin Gerry, energy analyst with Raymond James Financial in St. Petersburg, Fla.

"While energy did pull back, it wasn't to the extent of some other market areas because its main driver remains $70-a-barrel oil."

He is bullish about energy for the long haul, predicting powerful growth rates throughout the coming decade.

"You really have to think long term with energy and can't be a short-term trader," said Dan Hassey, senior research analyst with the Gold & Energy Advisor newsletter in Boca Raton, Fla.

"The one thing that could make oil prices lower in the short run is a global recession, because lower demand would drive down prices, but they will still only go down just so much because OPEC will cut the supply."

Not everyone has the temperament to look patiently toward the future without suffering a few nervous twitches over the present. Some experts voice reservation about these stocks because they question the more optimistic estimates of world demand.

"Volatility in oil prices will continue because I don't think oil prices at $70 a barrel are justified by the current supply and demand," said Fadel Gheit, energy analyst with Oppenheimer & Co. in New York. "Demand is lower than many people think, and, despite OPEC cuts, inventory is still high."

Gheit is not investing in any energy stocks now because the near term remains uncertain.

"It's like trying to catch a falling knife, so you should wait until it hits the ground to pick it up," he said.

Shares of Diamond Offshore Drilling are recommended by Glickman and Hassey, while Transocean and GlobalSantaFe are recommended by Gerry and Glickman.