Analyst upgrades:

• Barclays upgraded Dollar Tree (NASDAQ: DLTR) to Overweight from Equal Weight and raised its target to $64 from $48 following the better-than-expected Q2 report.
• Cowen upgraded Whirlpool (NYSE: WHR) to Outperform from Neutral. The firm cites stabilizing demand trends and recovering margins for the upgrade.
• Susquehanna upgraded Isle of Capri (NASDAQ: ISLE) citing weakness following the weak quarter. The firm, which has a $13 target on shares, expects regional operators to benefit from improving macro trends quicker than destination markets.
• Senior Housing (NYSE: SNH) was upgraded to Outperform from Market Perform at Wells Fargo.
• Barclays (NYSE: BCS) was upgraded to Outperform from Market Perform at Keefe Bruyette.
• CGI Group (NYSE: GIB) was upgraded to Buy from Speculative Buy at Canaccord.

Analyst upgrades:

• Citigroup upgraded National Fuel (NYSE: NFG) to Hold from Sell to reflect better than expected drilling results for the company's Marcellus shale assets. Citi raised its target on shares to $43 from $42.
• Baird upgraded Netezza (NYSE: NZ) to Outperform from Neutral and raised its target to $14 from $7 based on the company's new product announcement and potential revenue acceleration.
• JPMorgan upgraded Liberty Interactive (NASDAQ: LINTA) to Overweight from Neutral. The firm finds the valuation attractive following Liberty's better than expected Q2 results and set a $13 price target on the stock.
• Marlin Business (NASDAQ: MRLN) was upgraded to Outperform from Market Perform at William Blair.
• Paychex (NASDAQ: PAYX) was upgraded to Sell from Conviction Sell at Goldman.
• Hewitt Associates (NYSE: HEW) was upgraded to Buy from Neutral at UBS.

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.

Chris Mayer, editor of Capital & Crisis, chose Rosetta Resources (NASDAQ: ROSE) as his favorite stock for 2007, which rose 32% as of 6/1/07. Here is his original recommendation for Rosetta and his current opinion on the stock.

For his new top pick, National Fuel Gas Co. (NYSE: NFG), he says, "I love companies with 'hidden assets,' things that have been lying around gathering dust but suddenly turn into something very valuable. It's like finding an old Mickey Mantle baseball card in Dad's attic.

"One stock that is a hidden asset in the Appalachians is National Fuel Gas. Like an old baseball card, it's been around a long time. NFG incorporated in 1902, though its predecessor companies are much older. It is an integrated gas utility. This means it is involved in every aspect of natural gas, from the bottom of the well to the burner tip.

"NFG has its own exploration and development company, with oil and gas reserves across many states (45% of production is oil). It has a regulated utility serving 727,000 customers in New York and Pennsylvania.

"It owns nearly 3,000 miles of pipeline, along with 32 storage fields. NFG also owns over 100,000 acres of black cherry hardwood in Pennsylvania. Finally, NFG has a small energy broker business with some 25,000 customers.