"Railroads are a play on three big secular themes: the drive for increased energy efficiency, growth in coal and the agriculture boom," says Elliott Gue, a energy sector expert who has just returned from Japan where he was covering the G8 Summit.

Meanwhile, in his The Energy Srategist, he states, "Railroads are now among the most fuel-efficient forms of freight transport available." Here, he offers a bullish review of Union Pacific (NYSE: UNP).

"My long-held thesis on the group has been that the railroads are no longer totally dependent on the US economy for their growth.

"It's no longer appropriate to look at this sector as viciously economy sensitive. The traditional relationship between the broader market and the rails has been breaking down for several years, but this trend appears to be accelerating.

"In 2007, according to the Association of American Railroads (AAR), the average railroad moved a ton of freight a distance of 436 miles on a single gallon of diesel fuel. That makes freight trains roughly three to four times more fuel efficient than trucks.

"Union Pacific is the largest railroad in the US and has long been one of my favorites. The company's network is nearly 33,000 miles long and is concentrated in the West and Midwest. It also offers a convenient example of the bullish forces at work for the rails, particularly in the coal and agriculture industries.

For 25 years, Steven Halpern, editor of TheStockAdvisors.com, has surveyed the leading financial newsletter advisors asking for their favorite stocks for the coming year. This article is one of 100+ ideas in the Best Stocks for 2008 report.

"My favorite aggressive recommendation for 2008 is Acergy (NASDAQ: ACGY)," says Elliott Gue, editor of The Energy Strategist.

"Acergy provides engineering and construction services for offshore oil and gas developments with a particular focus on deepwater projects. Acergy's most important business is what's known as SURF -- subsea umbilicals, risers and flowlines.

"SURF relates only to wells that are developed with subsea completions, meaning that the well is installed directly on the seafloor. When wells are installed on the seafloor, operators need ways to control the well remotely.

"This is done via electrical and hydraulic systems; umbilicals are nothing more than electrical and hydraulic cables that connect a surface-based platform to subsea wells. The term riser refers to a flexible steel pipe that connects underwater pipelines or wells to surface-based floating production platforms. Risers actually carry oil and/or gas from subsea developments to the surface.

"Finally, flowlines are smaller diameter pipes used to transport oil and gas underwater. Obviously, all subsea developments require the installation of SURF. Acergy's heavy concentration in this area gives it extraordinary leverage to deepwater.

"The big, integrated oil companies are known for their relative safety and stability, and most have been paying dividends for many years " says energy expert Elliott Gue.

In his The Energy Strategist he explains, "These have been among the most reliable stocks investors can own in the long run." Here, he looks at Chevron (NYSE: CVX), which he calls his favorite among the US independent oil companies.

"Chevron remains relatively cheap in three valuation measures: price-to-barrel of oil equivalents; price-to-earnings and price-to-cash-flow. And while its 2.7% yield doesn't exactly make Chevron an income stock, it's consistently boosted that payout over time by more than 10% annualized over the past five years.

"Chevron is also one of the only Super Oils that will show meaningful growth in production over the coming few years. Even more important, it's scheduled to start up four major projects over just the next two years that will generate significant production growth upside near term. Here's a quick rundown:

"Tahiti is a deepwater field in the Gulf of Mexico where Chevron holds a 58% stake. The field is expected to have a peak production rate of 125,000 barrels of oil per day and 70 million cubic feet of natural gas.

Last December, over 100 stocks were featured in our Top Picks for 2007 report. Now, at mid-year, we turn to the 20 advisors whose picks showed the strongest gains to get an update on their previous picks, as well as a new favorite stock for the second half of the year.

Elliott Gue, editor of The Energy Strategist, chose Energy Metals Corporation (ASE: EMU) as his top pick for 2007. The stock has gained 100%; the company received a takeover bid from SXR Uranium One (OTC: SXRFF) on June 4, 2007.

For his new top pick, the advisor says, "One of my favorite sectors right now is coal. While coal isn't the most environmentally friendly of fuels, it accounts for more than 50% of all energy produced in the U.S. and has an even higher share in developing markets like China.

"I see little chance that coal will lose its pre-eminent status over the next decade. In addition, new uses for coal are emerging. In the U.S., the government is looking to promote the use of coal-derived liquid fuels with a series of subsidies and tax breaks; even the military is exploring the use of coal-derived fuels.

"My top play on the coal sector is Peabody Energy (NYSE: BTU), the largest coal miner in the U.S. The company is spinning off its high-cost mining operations in the eastern U.S. into a separate firm.

"Meanwhile, Peabody has the largest position in the prolific and rapidly growing coal-producing basin of the West, the Powder River Basin. Even better, the company recently acquired Australia's Excel Coal -- Excel is a major exporter of Australian coal to China. Chinese coal demand is growing rapidly, and Peabody is well placed to take advantage."

I've just returned from the World Money Show in Orlando where more than 10,000 investors gathered to learn about global investing. I had a chance to meet with many of the U.S. and foreign financial experts featured at the show, and over the next week I will share some of their top investment ideas. To view all of the stocks featured in this special global report, click here.

"One of my favorite long-term growth themes is biofuels," says Elliott Gue, who believes this sector is "locked in a longer-term secular bull market." Says the editor of The Energy Strategist, "Among individual stocks in the biofuels sector, investors can look at Monsanto (NYSE:MON), Potash Corp. (NYSE:POT), Mosaic (NYSE:MOS) and Syngenta (NYSE:SYT).

"My basic outlook for all of these stocks is that pullbacks of 10% to 15% are possible from time to time, but I still I regard such selloffs as outstanding buying opportunities. In addition to these selections, I'm adding PowerShares Deutsche Bank Agricultural Fund (AMEX:DBA) to my biofuel coverage.

"The DB Agricultural Fund doesn't hold any stocks at all. This fund instead buys commodity futures contracts, a market where the majority of stock investors have little or no exposure. The fund holds a quarter of its assets in corn futures, a quarter in wheat, a quarter in soybeans, and a final quarter in sugar.

"These are the most-important traded agricultural commodities. Therefore, the fund is a good play on the overall bull market in agricultural commodities I see developing in coming years.