Is your favorite stock on fire? Has it gone up in the last couple of weeks on no or limited news? One of my favorites, Intuitive Surgical (NASDAQ: ISRG), has already gained more than 100% this year and continued to fly over the past month reaching yesterday a 52-week high of $256.76 from a 52-week low of $95.00.

This is not the only high flyer. Apple Inc. (NASDAQ: AAPL) finished the day at $167.91, up $6.46 and Amazon.com (NASDAQ: AMZN) closed out the day at $95.85, another 52-week high, and both are up over 100% this year also. Adding to the momentum picture, Google Inc. (NASDAQ: GOOG) finally topped $600 closing at $609.62 or nearly a 3% gain on a day the market was down. Are there Ghosts in the Machine?

I can name many stocks that just won't quit. What's going on? Are we building up towards earnings reports that won't sustain these numbers just to watch profit taking or disappointment cut these stocks down to size? I have no idea, but I'm sure that stocks rising on no news day after day have either become speculative momentum plays or inside information is running through some brokerage houses. I believe the former, not the latter, but would love to hear some facts from anyone who has some. Otherwise, while I'm enjoying the ride, my skeptical side is telling me the music has to stop soon.

To find potential opportunities and verify my track record, read Chasing Value or Serious Money.

Sheldon Liber is the CEO of a small private investment company and the principal for design and research at an architecture & planning firm.

Is it ever OK to forget valuation? Yes -- if you have the right mindset.

Once I learned how companies were valued, and how to value companies, I found it increasingly difficult to trade stocks that I may have found interesting before. The idea behind investing is that the stock market offers you businesses at premiums and discounts to their values. Obviously, to make money, you try to purchase the stocks with the deepest discounts and wait for the market to realize their value. However, this certainly has its flaws -- namely, you might have valued the company incorrectly. If you have too much conviction in this valuation, you can stand to lose a lot of money.

Trading is different from investing because you don't look at a stock as a business -- you look at it is a "stock." This mindset has its benefits over investing -- primarily the fact that money management becomes much easier because you can quickly cut losses without guilt.

Prior to learning about the concepts of value investing, I would guiltlessly trade in and out of stocks based on which sector was hot, momentum in earnings, and even momentum in price. And I happened to do well, but when another commitment came up (school) I was forced to shift to a more long-term mindset.

Each year Steven Halpern, editor of TheStockAdvisors.com, surveys the leading financial newsletter advisors asking for their favorite stocks for the coming year. This article is part of his 24th annual Top Picks Report.

CDC Corp. (NASDAQ: CHINA) is a favorite speculative idea for 2007 from momentum trading expert, Kevin Kennedy. The editor of The Coolcat Report notes, "CDC operates companies focused on enterprise software applications and services, mobile applications, online games, and the Chinese portal China.com.

"The company's software solutions are used by more than 5,000 customers worldwide within the manufacturing, financial services, health care, home building, real estate, and wholesale and retail distribution industries.

"Its China.com unit is a leading Mobile Value Added Services (MVAS) provider and Internet services company operating principally in China. CDC Mobile is focused on providing MVAS products to subscribers in China. CDC Games Limited is one of the market leaders of online and mobile games in China with more than 37 million registered users.

"CDC reported blowout third-quarter results in November. Total revenue was $78.2 million, an increase of 26%. Earnings per share tripled to $0.09 per share. Future plans include an initial public offering of either CDC Software or CDC Games and a continued emphasis on acquisitions. The stock is on a five-month win streak, including a 41% surge in November."