Some companies are obviously great investments -- in hindsight. Yet for every stock out there screaming "buy me," others simply give us a nudge and a nod. How can we tell tomorrow's obviously great 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 5,300 starred companies, but are just shy of superstardom. While all the attention might be focused on their five-star peers, we can sift through CAPS to find four-star stocks approaching greatness. Here are a handful:

  • Halliburton (NYSE:HAL)
  • Spectrum Pharmaceuticals (NASDAQ:SPPI)
  • Western Refining (NYSE:WNR)
  • American Capital (NASDAQ:ACAS)   
  • JA Solar (NASDAQ:JASO)

Some of these names might surprise you. After all, oil fields expert Halliburton has been an industry leader for 80 years. Almost great? It's a reminder that even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten their potential. However, the 140,000-plus CAPS members chose these companies as less obvious sources for tomorrow's great buys, so let's see why they might merit your attention.

In the sight of greatness?
The incongruity of American Capital's appearance here is striking. The company had to get its lenders to agree not to sue it for collection on $393 million of privately placed notes, agreeing to add an additional $21 million in "make-whole" payments in exchange for the forbearance.

Yet investors look at the dividends it's still able to pay and, like CAPS member mantonino, find there's good pickings for the value: "Very low for the value. The dividends were fantastic for current holders - just need to get in this at the right time and you're riding with virtually a free ride."

While Allied Capital (NYSE:ALD) is also struggling and posting its sixth consecutive quarterly loss, American Capital has realized decent gains by selling a number of its assets. The business development company says that since the beginning of last year's fourth quarter it's received $700 million from realizations of portfolio investment repayments and exits, including exiting more than 20 of its portfolio companies.

Most recently, it sold an unnamed company for $37 million, realizing a $17 million gain on the transaction, which amounts to a return of 39%, including the interest and fees it earned over the life of the investment. Still, Standard & Poor's lowered its credit rating of American Capital because overall earnings deterioration has accelerated and its portfolio companies have underperformed.

A chilly reception
Few industries have held up well in this recession, but oil refiners are suffering a cruel and crude fate that's led some of the leaders, like Valero (NYSE:VLO), down an oil-slicked slope. Crude oil stockpiles reached a 26-year high, sending oil prices below $69 a barrel, leading refiners to resort to cutting output to increase processing profits.

For CAPS member Option1307, small refiners like Western Refining are considered "sure bets" that will gain in the years ahead despite risks:

They may not rise instantaneously but within a few yrs. this will be a huge winner. [Western Refining] is not located along the gulf coast which is excellent to keep in mind considering we are entering hurricane season.

To be fair, [Western Refining] does have a significant amount of debt and this is somewhat of a concern for me; however, I don't feel it is an umanagable amount.

A great opportunity for you
Investor sentiment suggests these four-star investments are on their way to five-star greatness, but it pays to start your own research on Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made -- all from a stock's CAPS page.

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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 gold-plated disclosure policy.