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 5,300 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 companies approaching greatness. Here are a handful.

  • Amgen (NASDAQ:AMGN)
  • Bucyrus International (NASDAQ:BUCY)
  • Clean Energy Fuels (NASDAQ:CLNE)
  • Pan American Silver (NASDAQ:PAAS)
  • Skyworks Solutions (NASDAQ:SWKS)

Some of these names might surprise you. Amgen, for example, has been a leading name in biotechs almost since the industry came to the fore. 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 140,000-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 cap-and-trade debate is generating a divide in the business community. Some companies -- like nuclear power operator Exelon (NYSE:EXC) -- believe their business will benefit from cap-and-trade. They've even gone so far as to quit the U.S. Chamber of Commerce because of that body's opposition to the Waxman-Markey bill. Exelon estimates it will be able to grow revenue by $1 billion a year if the climate change regulations pass, because its noncarbon-based energy won't be subject to the carbon caps-and-trades. Duke Energy (NYSE:DUK), which also supports the bill, has estimated cap-and-trade could raise the cost of electricity by 40% in some areas.

However, some investors remain wary of the energy sector, specifically "almost great" natural gas provider Clean Energy Fuel. CAPS members have not given it the highest five-star ranking.

Certainly T. Boone Pickens has been doing his part to change that. For instance, he's been pushing for legislation that would end up benefitting the company (of which he happens to own 31%). His revised "Pickens Plan" would make natural gas the focal point for future energy needs, and he's been trying to persuade the government to move toward converting the nation's trucking fleet to natural gas. Clean Energy Fuels is a large provider of natural gas for transportation in North America, with almost 200 fueling stations across the U.S. and Canada. It also operates two liquid natural gas production plants.

The primary use for natural gas is for heating, but with low demand and high inventories, the price has dropped to record lows. That was a contributor to Clean Energy's wider-than-expected loss in the just-reported third quarter. Getting the nation's truckers to fill up at the stations would help generate additional demand and boost pricing. Of course, as Pickens likes to point out, it would also help the U.S. save 2.7 million barrels of oil a day.

Made in the shade?
Overall, 97% of the 866 CAPS members rating Clean Energy Fuels see it outperforming the broader market. Despite my reservations about Pickens' motivation and how getting diesel trucks converted to natural gas would benefit his company, the oil savings is a powerful argument.

A great opportunity for you
While I'd like to vote against it just on principle, I've instead headed over to Clean Energy Fuels' CAPS page and marked it to outperform the market over the next year or so. But CAPS isn't about what I think as much as it is about what you all think. What's your position? Go rate Clean Energy Fuels yourself, or let us know in the comments section below how you feel.

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