Is oil at $80 per barrel a price tantamount to a bubble? At least one analyst thinks so.

"It's a bubble and we don't know when it's going to go bust, but it's just a question of time," said Eugen Weinberg, a senior analyst with Commerzbank AG in Frankfurt, told Bloomberg News Monday. "So enjoy the party but stay close to the door."

Air travel continues in a state of flux thanks to a "huge cloud of ash" emanating from an Iceland volcanic eruption. In fact, this cloud of ash has covered half of Europe and caused the "largest disruption of air travel since the Sept. 11, 2001 terrorist attacks."

After 6,000 flights were grounded yesterday, 17,000 are expected to remain on the tarmac today. What is the problem? Volcanic ash can block engines and cause them to fail. The problem isn't only in Europe, it has forced the cancellation of half of all trans-Atlantic flights. With thousands of air travelers stranded across the globe and no end in sight, is this another black eye for air carriers?

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."

See all 20 stocks the advisors picked for the second half of 2007.

MAJOR PAPERS:

• The Wall Street Journal's (subscription required) "Heard on the Street" column focused on companies that would be hurt the most by the price of oil continuing to fall. The article mentioned Hess Corp (NYSE: HES) and Suncor Energy (NYSE: SU), along with alternative energy companies Aventine Renewable Energy Holdings (NYSE: AVR), Pacific Ethanol (NASDAQ: PEIX) and VeraSun Energy (NYSE: VSE).

OTHER PAPERS:

• French newspaper Les Echoes reported that United Parcel Service (NYSE: UPS) may cancel its order for 10 Airbus A380s, which could create an opportunity for Boeing (NYSE: BA).
• Light Reading reported that Tellab's (NASDAQ: TLAB) CTO Thomas Gruenwald will leave the company at the end of this week.
  
• Investor's Business Daily's "New America" column mentioned BMC Software (NYSE: BMC) positively.
• BusinessWeek's "Inside Wall Street" column mentioned Volcano (NASDAQ: VOLC), UCBH Holdings (NASDAQ: UCBH) and US Airways Group (NYSE: LCC) positively.