Some companies are obviously great investments -- in hindsight. Sure, we should have bought Starbucks at its IPO and earned a thousands-of-percent return 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 obviously great investments from the thousands of pretenders?

The stars' walk of fame
On Motley Fool CAPS, these opportunities exist among our four-star stocks. In CAPS' proprietary ratings system, they rank higher than most of the other 5,500 companies in the CAPS universe, but they're just shy of superstardom. While their five-star peers get all of the attention, we can sift through CAPS to find the four-star companies approaching greatness. Here are some possibilities:

  • Mylan Laboratories (NYSE: MYL)
  • Encysive Pharmaceuticals (Nasdaq: ENCY)
  • NovaGold Resources (NYSE: NG)
  • Universal Display (Nasdaq: PANL)

Some of these names might surprise you. Generic-drug maker Mylan, for example, has been providing low-cost alternatives to name-brand drugs for some time. 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 89,000-plus CAPS investors chose these companies as less obvious sources for tomorrow's great buys, so let's see why they might merit your attention.

Making tracks for profits
Most of us are familiar with light-emitting diodes, or LEDs, if for no other reason than that we might have worn a way-cool LED watch back in the 1970s. Well, LEDs have come a long way since then; these days, they represent the next generation of lighting technology that has the likes of General Electric (NYSE: GE) and Philips scrambling to scoop up LED manufacturers.

Yet imagine an LED technology that goes even one step further. Imagine super-thin TV screens that you can roll up and take with you, or a "heads up" display on your car's windshield while you're driving. That's the promise of organic LED technology, or OLEDs, and Universal Display could be one of the leaders. Yet before we get to that futuristic technology, we'll probably see OLEDs being used to make our current crop of televisions better, and for that, Universal has been signing up partners such as Sony (NYSE: SNE). That has some Fools drooling over the potential gravy train.

CAPS investors feel the same way. Some 95% of the investors rating the Motley Fool Rule Breakers recommendation see Universal as outperforming the market. CAPS player 07acuratls, for example, believes it's only a matter of time before OLED screens go mainstream:

[Universal Display's] OLED technology is the next generation of video displays, ultimately replacing the common LCD and Plasma displays. Once scientists master the [development] of this technology and achieve many of the potential efficiencies of this type of lighting, this will become mainstream. And once that happens, this stock is going way higher.

Another CAPS player, blitztech, thinks Universal's patent portfolio will finally come into play as the rollout of OLED screens hits the market. When that happens, says blitztech, Universal should outperform not only the market but its rivals as well:

This company is finally selling licensing and is ramping up [its] connections to get manufacturing started in the right direction. ... It has been [hemorrhaging] money for years and is finally showing shining examples of what [its] 800 patents are capable of. This is one of the only players in the field that will actually get [its] ... products on the market and with the intellectual property rights and agreements in place it is poised to perform!

A great opportunity for you
You've heard the latest on Universal Display, 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's completely free. Let's us hear what you have to say about the great and almost great companies that interest you.