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 5,400 starred 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 firms approaching greatness. Here are a handful:

  • DRDGOLD (NASDAQ:DROOY)
  • Vical (NASDAQ:VICL)
  • Resource Capital (NYSE:RSO)
  • Nokia (NYSE:NOK)

Some of these names might surprise you. Nokia, for example, despite recent difficulties, remains the worldwide leader in cell phone sales. 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 150,000-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?
With the hype and horror of a worldwide swine flu pandemic thankfully receding into the past, innovative biopharmaceutical specialist Vical can focus its attention on other areas that might have a longer-lasting impact on the company.

It has prioritized its R&D efforts to concentrate on those areas where it can most quickly proceed to commercialization, such as its recently completed phase 3 enrollment for trials of its Allovectin-7 metastatic melanoma treatment, which it estimates has a worldwide market surpassing $500 million.

The new focus is attracting CAPS members. JuanPeter, for example, likes where Vical is heading, but is mindful of the stumbles biotechs can take along the way:

I think that the stock will outperform due to the expectations made on the potential outcome of its Allovectin-7 phase III trial. But right now I wouldn't buy it at all. I'll tell you why: few years ago, in 2002, they carried out a similar trial in phase III, at that time they wanted to evaluate combined administration of allovectin plus chemotherapy regarding its improvement in clinical response versus chemotherapy alone. They didn't meet the main endpoints and the share went down dramatically that year.

It's important to note that not everything rides on Allovectin-7. The company also has two licensed gene therapies for peripheral arterial disease (one with sanofi-aventis (NYSE:SNY)), as well as a continuing contract with the U.S. Navy to pursue DNA technology that can speed up the creation of vaccines, including for the H1N1 virus.

A wing and a prayer
And what of the issues confronting Nokia? It is facing an onslaught of competition from Apple (NASDAQ:AAPL), Research In Motion (NASDAQ:RIMM), Palm, Google, and Motorola. It experienced delays in bringing new products to market, and it was only in this past quarter that it finally saw an increase in average selling price for its handsets, after seeing that metric decrease in every single quarter since 2004. It's also in the middle of a tit-for-tat patent-infringement legal wrangle with Apple over their respective technologies.

CAPS member huthuthike sees the miscues finally catching up to Nokia and believes it might be time for a leadership change:

Their lack of vision and ability to create compelling smart phones is catching up to them. It appears they may have landed into the typical big company trap. Too many VPs battling over turf and too little visionary innovation and business development practices over issues that really matter. I'd think they need to streamline in a big way. Reduce the number of developments and VPs with associated overhead. They need a visionary who can unify the company in terms of its roadmaps, innovation, and business development initiatives.

Most CAPS members, though, come down on the side of the cell phone leader; more than 92% of the nearly 2,700 members who've rated it believe it will outperform the market. You can dial up their opinions on Nokia's CAPS page and tell us whether you think it's time to hang up on the company.

A great opportunity for you
Investor sentiment suggests these four-star investments still seem to be on their way to five-star greatness, but 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.

Nokia is a Motley Fool Inside Value selection. Google is a Rule Breakers pick. Apple is a Stock Advisor recommendation.

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.