"I am getting more interested in natural gas; we all realize that crude oil production is peaking and that new discoveries are deep, dangerous to exploit, and bottom line expensive," says resource expert Curtis Hesler.

The editor of Professional Timing Service explains, "Investors can consider Natural Gas Service Group (NGS), a natural gas field equipment provider that I am adding to our recommended list.

"While technology is improving in wind and hydroelectric generation, perhaps the greatest technical strides are being seen in natural gas production.

Analyst Upgrades

• BofA/Merrill upgraded ConocoPhillips (COP) to neutral from underperform following the better-than-expected Q2 report. The firm has a $61 price target on shares.
• Deutsche Bank upgraded Citrix Systems (CTXS) to buy from hold following the company's Q2 results and raised its target for shares to $65 from $45. Shares were also upgraded to neutral from underperform at Cowen following the better-than-expected Q2 report.
• Macquarie upgraded Arch Coal (ACI) to outperform from underperform and raised its price target to $29 from $23. The firm expects PRB priced to move higher given increased domestic and export demand combined with supply shortfalls.
• Boeing (BA) was upgraded to hold from sell at Societe Generale.
• Equinix (EQIX) was upgraded to outperform from perform at Oppenheimer.
• Williams-Sonoma (WSM) was upgraded to equal weight from underweight at Barclays.

MOST NOTEWORTHY: Oil and gas services companies, mining companies and Moody's Corporation (NYSE: MCO) were today's noteworthy upgrades:

• Morgan Keegan upgraded Natural Gas Services Group Inc (AMEX: NGS), Basic Energy Services Inc (NYSE: BAS) and Complete Production Services Inc (NYSE: CPX) to Outperform from Market Perform and Patterson-UTI Energy Inc (NASDAQ: PTEN) to Market Perform from Underperform, as the firm has a bullish outlook for drilling activity in the back half of 2007 and into 2008.
• JP Morgan upgraded shares of both Compania de Minas Buenaventu (NYSE: BVN) and Goldcorp Inc (NYSE: GG) to Overweight from Neutral on valuation.
• Moody's was upgraded to Overweight from Equal Weight at Morgan Stanley, citing increased confidence in revenue outlook and growth drivers.

OTHER UPGRADES:

• Inverness Medical Innovations Inc (AMEX: IMA) was upgraded to Buy from Hold at Stifel Nicolaus.
• Credit Suisse upgraded shares of Johnson Controls Inc (NYSE: JCI) to Outperform from Neutral, citing growth outlook in the company's building efficiency business.
• Allianz SE (NYSE: AZ) was upgraded to Buy from Add at WestLB on valuation and the company's strong Q1 results.

Gasoline inventories dropped below their five-year average and are now 6% below last year's average, according to Joseph Dancy, an adjunct professor at Southern Methodist University, in an essay published in Barron's this weekend.

This means the outlook for investing in energy remains good, Dancy believes, as demand for gasoline will grow 2% with little supply relief in sight. Particularly the lack of new refinery capacity means positive growth prospects for a company like Matrix Service Company (NASDAQ: MTRX) that specializes in repair and maintenance services to the refining, distribution and pipelines sectors.

Dancy wrote the supply and demand balance for energy could mean a sharp escalation of energy prices. Mexico's Cantarell field's output, the second largest in the world as measured by output, declined 17% in March from year-earlier levels, while offset by new production increases at a nearby field, total crude production from Mexico is down 5%. In addition, Venezuela production should get hit at some point as Chavez has taken control of exploring for and producing energy away from the foreign experts. And Nigeria, who sends 1 million barrels per day to the US, is also in a politically tenuous situation.

Add to this, the huge swing producer, Saudi Arabia, announced that is will no longer increase production after 2009, which might indicate the nature of its oil reserves.

In addition to Matrix, Arena Resources Inc (NYSE: ARD), OMNI Energy Services Corporation (NASDAQ: OMNI), Pioneer Drilling Company (AMEX: PDC), Natural Gas Services Group Inc (AMEX: NGS) were mentioned as attractive investment ideas.