I don't have to remind you that more than a few sectors are having a tough go of things so far in 2008. As a Rational Investor, I like to buy shares of great companies like Fortune Brands (FO) and FedEx (FDX)that reside in beaten-down sectors.

(By the way, to learn more about these two stocks, you'll want to read, "FedEx Corp (FDX): Still on Time" and "This King of Brands Will Make You a Fortune!")

On the flip side of the coin, I also think that there is plenty of room in Rational Investor portfolios for companies that operate in the hot sector du jour. And right now, commodities are one of the hottest sectors these days, particularly the coal industry.

Why Coal Is King

Coal is much maligned, but extremely useful. Al Gore and the green lobby hate it, since it contributes to global warming. I get it. But coal is what we've got. In fact, coal is to the United States what oil is to the Saudis.

Coal is used to heat our homes, power our manufacturing plants (most notably in the production of steel–another industry enjoying profitable times these days), to help reduce our dependence on foreign oil, not to mention, provide thousands of American jobs and millions in tax revenue.

Worldwide demand is soaring as developing nations like China build out their electrical grids and construct new skyscrapers. In fact, current U.S. exports are expected to be in the range of 75 million to 79 million tons this year alone.

Arch Coal's Future Burns Bright

Arch Coal (ACI) produces and sells metallurgical and steam coal from surface and underground mines to power plants, steel mills and industrial facilities throughout the United States.

Currently, it has 18 active mines with roughly 2.9 billion tons of proven and probable recoverable reserves. With analysts predicting a meteoric rise in coal prices through next year, Arch Coal's CEO, Steve Leer expects exports to reach 100 million tons by 2010.

ACI trades for just 13 times fiscal '09 estimates, making it nature's (and Wall Street's) dirty little secret.

Coal is back! And it's hotter than ever! Stop burning a hole in your portfolio with overpriced oil plays. Sign up for your risk-free trial subscription to Richard Young's Intelligence Report and he'll show you which top coal producers are raking it in for his Intelligence Report subscribers!