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, you can find these opportunities among our four-star stocks. In CAPS' proprietary ratings system, they rank higher than most of the other 5,300 starred companies, but they're just shy of superstardom. While their five-star peers get all the attention, we can sift through CAPS to find the four-star companies approaching greatness. Here are a handful:

  • American Eagle Outfitters (NYSE:AEO)
  • Force Protection (NASDAQ:FRPT)
  • IntercontinentalExchange (NYSE:ICE)
  • Massey Energy (NYSE:MEE)
  • SanDisk (NASDAQ:SNDK)

Some of these recognizable companies might surprise you -- yet 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?
The longtime relationship between SanDisk and Samsung almost blossomed into marriage last year, as Samsung made an offer to buy the memory-chip maker. But things got nastier than a snipe-fest between Joy Behar and Elisabeth Hasselbeck on the set of The View, and it all ended with Samsung backing out. Its high-profile, low-road letter did everything but accuse SanDisk of giving it a communicable disease.

Today, their coexistence is quite cold, but they stick together because there's still money to be made -- only SanDisk won't be getting quite as much as in the past. Its surprise second-quarter profit highlighted just how domineering it had been: It enjoyed 7% of total flash revenue royalties from Samsung, when the industry norm is around 1% to 2%. Now a new contract is set to replace the rapine nature of the old one and cuts the royalty in half. The new Samsung contract also doesn't cover 3-D memory and opens up the possibility that card and USB makers can sidestep SanDisk altogether and brand their own products purchased from Samsung. Still, Samsung remained in the fold -- and at a rate higher than typical for the industry.

What, then, of SanDisk's revenues going forward? NAND flash prices have improved, and manufacturers such as Micron (NYSE:MU) and Toshiba are poised to boost production. Yet if there's not enough demand to support that supply, pressure on average selling prices will begin to pressure SanDisk in turn. On the contrary, if the industry does recover, SanDisk could be well-positioned to capture the uptake. It was a give-a-little-to-get-a-little type of deal, although the tension in the household remains thick.

Investors believe that the memory maker is still on its way to becoming a company you'll remember. CAPS member DWHunt87 thinks SanDisk's SD cards are well on their way to becoming the industry standard, while pbMunkey thinks the royalties are enough to boost its valuation higher:

Still a takeover target. Great intellectual property. Royalties from [Samsung] alone shoul[d] make this stock be $20 / share.

Lumpy performance
The heat and humidity usually boil the inhabitants of the Northeast this time of year, but I've been enjoying the respite from high energy bills as summer temperatures have been cooler than normal. My air conditioners haven't had to come out of storage yet, and assuming I decide to sweat out the next few weeks if temps rise, they may not come out at all.

I suspect I'm not the only one not cranking the AC as much this year. The cooler weather, coupled with a recession causing slack business demand, mean that utilities are expected to see electricity consumption fall by 2% this year. Duke Energy (NYSE:DUK) isn't expecting an increase in industrial demand until 2011. Massey Energy said coal-burn rates at utilities in the Southeast fell 19% last quarter, while central Appalachian coal consumption dropped by 25% -- yet it was still able to turn lemons into lemonade.

With coal providing half of this country's electricity needs, investors think this abundant natural resource will continue to play a role in America's overall energy portfolio. As oil prices continue to creep higher, hovering near $70 a barrel at the moment, CAPS member sindelar14 thinks Massey is one of the industry's premier coal miners that will lead us forward: "With demand for oil going up, and most likely supply for oil dropping (PRICE INCREASE IN OIL), the alternative will be coal. These guys do coal best, and do it as clean as possible."

A great opportunity for you
Investor sentiment suggests that 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.

Duke Energy is a Motley Fool Income Investor selection. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Rich Duprey has no 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.