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.

Mark Skousen, editor of Forecasts & Strategies and host of the July 4th investor think tank FreedomFest, chose Aluminum Corp. of China (NYSE: ACH) as his favorite stock for 2007, which rose 45% as of 6/1/07. Here is his original recommendation on ACH and his current opinion on the stock.

For his new top pick, the advisor recommends Volcano Corp. (NASDAQ: VOLC). The advisor explains, "This is a medical technology company that is currently experiencing blockbuster revenue growth.

"Volcano provides a unique service in the burgeoning health care industry: an intravascular ultrasound and functional measurement product that visualizes the heart, brain, arteries, and other parts of the body to diagnose and treat heart disease, strokes, and other ailments.

"According to scientists and technicians worldwide, Volcano has the far superior technology than other competitors. I suspect that means a takeover in the future. Sales, which have raced past $100 million over the last twelve months, are growing at 48% per quarter. Earnings, too, have blown past analysts' estimates.

"I think this trend will continue for this stock. It could even become a buyout candidate. The stock has already started to move up. I recommend you buy Volcano now, before it erupts."