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 rated 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 that might be approaching greatness. Here are a handful of them.

  • The Buckle (NYSE:BKE)
  • PolyMet Mining (NYSE:PLM)
  • Progress Energy (NYSE:PGN)
  • Williams Companies (NYSE:WMB)

Some of these names might surprise you. Natural gas play Williams Companies, for example, has been powering up much of the West for years. 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 145,000-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?
There hasn't been a bit of copper, nickel, or other precious metals dug out of PolyMet Mining's Minnesota mine yet, but the permitting process has advanced to such a stage that it's on the verge of becoming a reality and should prove to be lucrative.

The NorthMet mine sits on one of the world's largest undeveloped deposits of copper, nickel, and other non-ferrous metals, and PolyMet controls 100% of it. The reserves at the mine were calculated when prices on these metals were substantially lower than they are today. For example, NorthMet's copper reserves were calculated at a price of $1.25 per pound, but today copper trades at more than $3.27 a pound. Similarly, nickel was priced at $5.60 a pound, yet it now goes for $8.63. Most telling, gold was valued at $400 an ounce at the time, and we're fairly familiar with where the yellow metal's price is today.

Little wonder, then, that as the time draws near for PolyMet to get its operations under way, investors are becoming more interested in the possibilities. CAPS member TheForest is looking for developments to break within the next year, while holyemo sees the ultimate production potential as an added benefit to the hedging aspects of the stock:

metal asset play-semi-hedge against inflation with commodities asset ownership; plus some hope of move to production/extraction

The miner's shares have already quadrupled in value this year, yet 93% of the CAPS members rating PolyMet believe it will continue to outperform the market. Teck Resources (NYSE:TCK) is another industrial metals miner that has experienced a strong surge of investor support, with shares up more than 600% year to date, and 97% of the CAPS members who have rated it back its ability to beat the S&P 500.

Why not head over to the PolyMet Mining CAPS page and add your opinion?

Try this on for size
Attracting a little more attention than PolyMet is women's clothing retailer The Buckle, one of the few retailers during this recession to consistently post positive same-store sales, and one that remains a good retail investment today.

CAPS member DanielSparks agrees with me, seeing Buckle as the retailer best primed for future success:

Undervalued. Best of its kind, when you look at the financial statements. Loaded with cash. Did great during the recession. A lot of room for growth.

Yet the start of the holiday season proved difficult even for this retailer, as same-store sales for last month rose less than analysts had anticipated. Indeed, for the Christmas selling season from Nov. 1 to Dec. 24, sales in the women's apparel sector fell 0.3%. While they actually rose 1.5% from Black Friday to Christmas, there was an extra shopping day in the period, so when looked at from that perspective, Buckle has continued to perform exceptionally. Compare that to Abercrombie & Fitch (NYSE:ANF), which hasn't experienced an annual increase in comps in almost three years.

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.

The Fool owns shares of Abercrombie & Fitch. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Rich Duprey does not have a 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.