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
The data shows that stocks achieving five-star ratings on Motley Fool CAPS have outperformed the market by 12 percentage points, and newly minted five-star stocks represent your best opportunity to capture those returns. So let's sift through the proprietary ratings system and find those stocks heading toward superstardom -- here's a handful of four-star firms approaching greatness:

  • Petrohawk Energy (NYSE:HK)
  • Pfizer (NYSE:PFE)
  • US Bancorp (NYSE:USB)
  • Western Refining (NYSE:WNR)
  • Williams Companies (NYSE:WMB)

Some of these names might surprise you. Pfizer, for example, has been developing blockbuster drugs for decades. 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 115,000-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.

In the sight of greatness
The "crack spread" that determines the profits of oil refiners like Western Refining refers to the difference in price between crude oil and the petroleum products like gasoline extracted from it. As oil prices soared, refiners like Western and Valero (NYSE:VLO) saw the spreads diminish thus narrowing their profits. While we are celebrating oil's fall in recent weeks, the refiners as well are rejoicing and CAPS member hateninja sees that and the hurricane season as reasons for hope.

[Western's] success relies largely on its ability to process crude oil into usable consumer products, such as gasoline, diesel, jet fuel and basic lubricants. This profitability is measured by what's called the crack spread... Due to rising crude oil prices in 2008, independent refiners such as Western have seen their share prices get slaughtered as the crack spread went negative. This has put them in the red with little hope in sight except for the current pullback in oil, and of course, the breaking news on the Weather Channel.

On the other side of that play are the oil and natural gas companies like Williams which have been enjoying the compounded growth of fuel prices. With the price of both oil and natural gas giving up ground, shares in these companies have pulled back as well. While the risks associated with the business are legion, CAPS member Manoncamelshump sees the concerns as being overblown because many of Williams' contracts are long term in nature and its risks have been diluted.

I believe Williams has most of its earnings from it's pipeline and midstream operations. Williams also has an E&P division but obviously that also make the company levered to the price of natural gas, a commodity risk that I think it is being punished for in an overdone way right now. Williams also has the risk as with any pipeline that if industrials slow ... throughput will decrease and its revenues will be hit. Then, again I think the bulk of their business is under long term firm contracts so not much risk there, and I like that they own the Transco line that runs from the panhandle to the major demand center in the East Coast.

US Bancorp is seen by many as one of the better financial institutions around that should survive the meltdown occurring at rival banks. Although their diversified revenue streams and higher spread assets bolster the situation, analysts fear that deteriorating credit quality, rising loan loss provisions, and pressures on margins weigh against it. In comparison, top-rated CAPS All-Star member mugwumper12 feels US Bancorp has positioned itself to take advantage of the weakness in its rivals.

Paulson finally did the right thing by letting Lehman fail. It's going to lead to the failure of other financial institutions, but it's also going to lead to a lot more consolidation... It's going to be a rocky road for the next 3 months as the financials unravel, but there will be a resolution to it now. There will also be some winners in the strong banks that are able to pick up the valuable assets of the failed institutions -- Bank of America, USB, and Wells Fargo (NYSE:WFC) look particularly well positioned here.

A great opportunity for you
These four-star investments are on their way to five-star greatness and 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 this completely free service, and let us hear what you have to say about the great and almost-great companies that interest you.

Bank of America, US Bancorp, and Pfizer are Motley Fool Income Investor picks. Pfizer is also an Inside Value recommendation. 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 disclosure policy.