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.

  • Banco Santander (NYSE: STD)
  • GT Solar (Nasdaq: SOLR)
  • Lear (NYSE: LEA)
  • Reed Elsevier
  • Visa (NYSE: V)

Even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold.

Spanish banking giant Banco Santander remains in better shape than its home country, although Venezuelan strongman Hugo Chavez is threatening to expropriate one of its subsidiaries. That's not a surprising move from Chavez. With a cyclical turn for the better in the European media sector, analysts are looking for increased advertising and corporate spending that should benefit publisher Reed Elsevier.

Since the 170,000-plus CAPS members have chosen these companies as less obvious sources for tomorrow's great buys, let's see why they might merit your attention.

In the sight of greatness?
 GT Solar is branching out into other markets to help offset the downturn expected in the solar industry. Specifically, the LED sector will be a future growth industry. GT saw that early and purchased a sapphire crystallization company last year, and has set about making deals to supplement its income.

Despite the bump reported by industry leader Cree (Nasdaq: CREE), as inventory issues play out, there's still plenty of upside potential here. LEDs are quickly leading to rumormongering, with Cree said to be in pursuit of Aixtron and pushing all sector stocks higher.

Yet as exciting as the potential is for LEDs to take off, CAPS member kcboy408 thinks it will be the green side of GT's business that carries the most weight:

Clean tech is still rising. I believe in mid to long term this will be good investment. Even for short term GT Solar had been doing well this year.

Dirt cheap?
The fact that Ford's (NYSE: F) stock is plummeting today in response to fourth-quarter results shows just how awesome its comeback has been. 2010 marked its biggest profit in a decade, some $6.6 billion, and the sell-off marks some serious shortsightedness. The automaker slashed its debt by more than half, generated 20% growth in sales -- double the industry average -- and its cars are now known for their quality. There's a buying opportunity if there ever were one.

Helping those results along, and being helped in the process, are parts suppliers like Lear and Johnson Controls, which themselves have had record years. Lear came back from bankruptcy and has taken charge to see its stock gain 60% in one year.

Short-sellers have been betting the parts supplier would stall again, but 94% of the CAPS members rating Lear believe there's additional market-beating performances revving up under the hood. You can tell us on the Lear CAPS page whether there's any spark left in its engine.

On the level
CAPS members haven't bought into the argument that the Fed's decision to limit debit card interchange fees to some 80% below what's currently charged will seriously damage transaction processor Visa.

Visa says the average volume per U.S. credit card has been surging lately, as American Express (NYSE: AXP) says earnings soared from people using their cards more while defaulting on them less. While the U.S. economy surpassed previous highs in the fourth quarter, causing some silly analysts to suggest we're beyond recovery and into expansion, the fact is the Fed fueled the growth with its policies. Our economy is still split in two. Wall Street's come out on top thanks to the taxpayer, and Main Street is still hurting.

Consumers are still going to rely upon their credit and debit cards to make their purchases and CAPS member witness1260 finds Visa financially fit as a result.

Everyone seems to have panicked because of credit card reform, but they'll be just fine. At the very least, they won't be hurt as much as the market seems to think. They have little long-term debt and earnings grew dramatically last year as people began spending more. Right now, they're way on sale.

Follow Visa on the Fool's free portfolio tracker to keep track of its progress.

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.