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.

Ken Kam, editor of Marketscope, chose two stocks in the Top Picks for 2007 report and both picks qualified him for our Top 20 Advisors. His selection of Valero Energy Corp. (NYSE: VLO) rose 48%. Here is his original recommendation for Valero and his current opinion on the stock.

In addition, Ken also picked Elan Corp. (NYSE: ELN) in our Top Picks 2007 report and its gain of 35% also qualifies among our Top 20 Advisors. Now, he is now re-recommending the shares as his current favorite for the balance of 2007.

The advisor explains, "Elan has been strong on rumors that Biogen (NASDAQ: BIIB) -- Elan's 50% partner for its multiple sclerosis drug Tysabri -- is interested in acquiring the company. Elan has also show recent strength on news that the company's Alzheimer's drug (AAB-001), which is partnered with Wyeth (NYSE: WYE), is being advanced to Phase 3 trials.

"When a stock makes a big move in a short period, there is a tremendous temptation to sell and 'lock in profits.' However, when the price move is accompanied with good news, the initial bump may be the start of a major move up. If you are too quick on the trigger, you may miss the bigger, longer term.