Let’s revisit Chesapeake real quick: A huge chunk of the US natural gas reserve is in Pennsylvania’s Marcellus Shale, and thanks to a new technology, horizontal drilling, we’re now able to tap most of it. Chesapeake owns nine of the 52 rigs in the Marcellus, as well as 1.45 million net acres there. This strong foothold makes the stock, Cramer says, “without a doubt, the single best way to play” it.

The price of natural gas could almost double next year, Cramer says, and XTO Energy is in great position to benefit from the move. Also, the company’s chairman, Bob Simpson, is helping to push the nat-gas agenda in Washington, which is essential to elbow out the powerful coal lobby.

Anadarko is up a colossal 66% since Cramer’s Jan. 12 recommendation, despite nat gas prices falling for much of the year. Imagine how the stock could do if the cost per thousand cubic feet reaches Cramer’s $6-$7 price target.

Sixty-six percent of this oil-and-gas driller’s properties are natural gas, and most of it is unhedged: just 35% for the fourth quarter and none at all for 2010. By not locking in customers early, Devon can now enjoy the full benefit of the commodity’s rebound. “If natural gas is really headed to $6,” Cramer says, “Devon’s the way to play it.”

Cramer isn’t the only person who thinks natural gas prices are headed higher. UPL CEO Michael Watford set his price target at $6, very close to the Mad Money host’s estimate. That’s probably why Ultra Petro is ramping up its drilling, especially in the Marcellus Shale. The company is digging 35 wells there, well above the originally planned 23.

Margins are crucial in any business, and EQT is an industry leader when it comes to natural gas. Right now the company’s finding and development costs come in at just $1.14 per thousand cubic feet, which is significantly lower than its peers’ $2.16. Management even boasted that it could bring that number down to $1 in its Huron Shale reserves, in Virginia, and said that costs are down big in the Marcellus as well.

Range Resources is another top-notch Marcellus Shale play. This wildcatter, as Cramer calls the companies that drill in hard-to-reach places, gets 86% of its 19.1 trillion cubic feet to 26.1 trillion cubic feet of reserve potential from the Pennsylvania nat-gas depository. Cramer also likes the solid balance sheet, with no debt coming due until 2012, and the possible sale of non-core assets to raise more cash. He thinks RRC “still has room to go much higher.”

“If you’re in the natural-gas drilling business,” Cramer said recently, “you’re going to have multiple years of good.” That’s why he’s so bullish on Halliburton.