Some companies are obviously great investments -- in hindsight. Sure, we should have bought Starbucks at its IPO and earned hundredfold returns 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 5,400 companies in the CAPS universe, but they're just shy of superstardom. Their five-star peers get more attention, but we can still sift through CAPS to find the four-star companies on their way to greatness. Here's today's list:

  • GameStop (NYSE:GME)
  • North American Palladium (AMEX:PAL)
  • RF Micro Devices (NASDAQ:RFMD)
  • StemCells (NASDAQ:STEM)

Some of these names might surprise you -- discount broker TD AMERITRADE, for example. Despite the problems that rival E*Trade (NASDAQ:ETFC) has suffered, TD AMERITRADE has been a stable part of the investing landscape for some time. Yes, even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold. However, the 85,000-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.

Not all that glitters is gold
For much of 2007, the precious metal palladium has traded between $320 and $380 per troy ounce, up only slightly from the year before. But this year, platinum's cousin has soared nearly 60%, rising more than 45% last month alone. That's the result of a power shortage in South Africa, where some 30% of the world's palladium is produced. (Russia accounts for more than half of palladium production.) Demand for the metal continues to grow, fueled by the auto industry (where it's used in catalytic converters), jewelry makers, and investors, and that continued demand helps force up prices.

That's good news for smaller producers such as North American Palladium, which supplies only about 5% of the world's market for the precious metal, along with another palladium play, Stillwater Mining (NYSE:SWC). However, it raises the question of whether palladium can reach the $1,100-per-ounce highs it hit a few years ago, when Russian supplies were interrupted. With demand rising, it looks as though there might be a sustained increase to palladium's price.

New CAPS player abbaman7 noted many of the same issues just a couple of weeks ago. The pitch describes why this player thinks the next five years ought to play out well for companies like North American Palladium:

"On the supply side, the key drivers are (i) the utility grid breakdown in South Africa ... (ii) the substantial drawdown of Russia's stockpile; and (iii) the significant increase in production activity from [North American Palladium]. ... On the demand side, multiple uses for palladium ... will result in demand exceeding supply... [P]alladium prices should continue to rise and could double within next 5 years."

Early this year, another CAPS investor, karmst04, found that the metal's eco-friendly attributes -- remember, the catalytic converter changes harmful combustion products into more benign ones -- make it a more alluring metal that will see its uses expand as a result:

"Palladium is ... very [versatile,] mostly used in cars but also in a variety of other products. Its an eco friendly material which is good for the green guys. ... It's a great green play."

A great opportunity for you
You've heard the latest on North American Palladium, but do you agree? Are these four-star stocks still investment-grade material? On Motley Fool CAPS, you can give your input and ultimately help to influence how they're rated. Outperform or underperform, near-term or well in 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.