Some companies are great investments -- in hindsight. Sure, we should have bought Starbucks at its IPO and earned hundredfold returns over the years. Yet for every stock out there screaming "buy me," others simply give us a nudge and a nod. How can we tell tomorrow's successful investments from the thousands of pretenders?

The stars' walk of fame
On Motley Fool CAPS, these opportunities can be found among our four-star stocks. In CAPS' proprietary ratings system, they rank higher than most of the other 5,300 companies in the CAPS universe, but they're just shy of superstardom. All the attention might be focused on their five-star peers, but we can sift through CAPS to find four-star companies approaching greatness, such as:

  • American Capital Strategies (Nasdaq: ACAS)
  • Hansen Natural (Nasdaq: HANS)
  • Melco PBL Entertainment (Nasdaq: MPEL)
  • Williams Companies (NYSE: WMB)
  • Zoltek Companies (Nasdaq: ZOLT).

Do some of these names surprise you? Hansen Natural, for example, has been highlighted as a small-cap company that's been one of the best stocks to own in the past 10 years -- a distinction it's held severalyears running.

But even small, undiscovered companies that have had spectacular runs still offer some of the best opportunities. We've forgotten the potential they still hold. However, the 81,000 CAPS investors chose these companies as less obvious sources for tomorrow's wise buys, so let's find out why they might merit your attention.

A roll of the dice
It's not exactly the Wild West -- there aren't any shoot-'em-ups happening, but Macau is perhaps one of the wildest gambling opportunities. A stub of land off the Zhanjiang peninsula, the Macau economy is dependent on the gambling and resort industries for its lifeblood. It is the only place in China where gambling is legal, and its success has countries like Japan considering allowing gambling to develop there.

Motley Fool Global Gains recommendation Melco PBL, a joint venture between two other gaming giants in the hemisphere, went public in 2006 and is actually seeing its shares trade at less than half the value of what its IPO was priced at. This despite the huge potential for growth and even as competitors like Las Vegas Sands (NYSE: LVS) and Wynn Resorts (Nasdaq: WYNN) expand operations in Macau. Yet Melco has been increasing its market share each month, despite suffering from higher costs, as it also expands its business.

CAPS investors like northcutt0 see past the initial losses Melco has posted as a result of cost overruns at their casinos, but note that it has an important asset: location. Its properties are near the Macau International Airport, so it's a natural first stop for arriving gamblers.

City of Dreams Casino and the 6-star Crown Macau will be two properties with the shortest drive to/from the Macau International Airport. That same strategy has been successful for the casinos closest to the Las Vegas International Airport like the MGM Grand.

Other investors like truubeliever see the long-term potential for revenues and profits make Melco a good bet for investors with a longer time horizon.

All negatives appear to be priced into the stock. Market for Macau casino stocks looking quite sour recently, but given the expectation of MAJOR revenues and profits from VIP operations at the Crown Macau, I expect MPEL to recover nicely. If you have the patience and tenacity to wait 3-4 years, the unquestionable success of the Crown and the City of Dreams will bring this stock to the $20++ range. Bottom feeders unite. This is the time to buy MPEL.

With 96% of CAPS investors rating Melco PBL Entertainment an outperform, they're willing to wager that odds are it will be a winner.

A great opportunity for you
You've heard the latest on Melco, but do you agree? Are these four-star stocks still investment-grade material? On Motley Fool CAPS, you can give your input, which can ultimately influence how they're rated. Outperform or underperform, near-term or well into the future, your opinion counts.

Sign up today for Motley Fool CAPS; it is completely free. Let's us hear what you have to say about the great and almost great companies that interest you.

Melco PBL is a Global Gains selection. American Capital Strategies is a recommendation of Motley Fool Income Investor. You can get a 30-day, free trial to any of the Fool's investment services.

Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy. Starbucks is a Stock Advisor selection.