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 other 5,300 rated companies, but they're 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 companies that might become great. Here are a handful:

  • Angiotech Pharmaceuticals (NASDAQ:ANPI)
  • Automatic Data Processing (NYSE:ADP)
  • Ivanhoe Energy (NASDAQ:IVAN)
  • Sequenom (NASDAQ:SQNM)

Some of these names might surprise you. Payroll processor Automatic Data Processing, for example, has been an industry leader for years. Almost great? Even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold. However, the 135,000-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?
Perhaps it's best known for its drug-eluting Taxus stent, which it markets with partner Boston Scientific (NYSE:BSX), but medical device maker Angiotech Pharmaceuticals has other promising developments.

Last month, Boston Scientific announced it was launching the third-generation Taxus stent, then said the Food and Drug Administration had approved the use of its small vessel stent, the TAXUS Liberte Atom, which it will launch this month. The FDA also granted Angiotech marketing approval for its Option Inferior Vena Cava filter, a device designed to filter blockages in an artery that feeds the lungs. With its Bio-Seal lung air leak technology also before the FDA for approval -- it was submitted to the agency at the same time as the vena cava filter -- there is the distinct possibility of more good news. Bio-Seal is already approved for marketing in Europe.

Of course, some "strategic alternatives" might play out as well. Back in November, Angiotech hired the Blackstone Group to pursue both a financial and a strategic restructuring. It completed the financial steps when it revised the terms for various notes coming due in the next few years, and it continues to explore other possibilities for its operations.

"Strategic alternatives" is often doublespeak for selling a company to the highest bidder. Royalty revenue from Angiotech's stent business has declined considerably in recent years, affecting its liquidity position. Competition has been fierce in the $4 billion-a-year stent industry, with Johnson & Johnson (NYSE:JNJ) leading the way, though its own market share has fallen dramatically as new rivals enter the market. And there's a report on a new study in The New England Journal of Medicine questioning the value of stents altogether. Angiotech might realize the most value for its business by ensuring its other medical devices get to market or making itself an appealing candidate for acquisition.

All-Star CAPS member zzlangerhans acknowledges the risks inherent in Angiotech's business:

Angiotech survived lows of 0.1 on viability concerns after taking on enormous debt to buy American Medical. While the soundness of that decision remains questionable. the stock recently brought 25-fold return to those who bought at the low. The share price has now withdrawn substantially from recent highs even as the company is looking more financially stable with improving stent royalty revenues and approval of additional devices. As long as they don't go [bankrupt], they should rise again from here.

Angiotech is rated better than the average three stars given to peer companies under the larger CAPS Pharmaceuticals sector tag. The 154 companies combine to rank among the top 100 industries with tags in the CAPS universe (out of 853 tags), rising more than 15% over the past month, even as the market rose only 4.6%.

A great opportunity for you
These four-star investments seem to be on their way to five-star greatness, and it pays to start your own research on these stocks 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.

Sign up today for the completely free service and let us hear what you have to say about the great and almost-great companies that interest you.

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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. The Motley Fool has a gold-plated disclosure policy.