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 5,400 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.

  • Alcon (NYSE:ACL)
  • Cypress Semiconductor (NYSE:CY)
  • Huntsman (NYSE:HUN)
  • Under Armour (NYSE:UA)

Some of these names might surprise you. Huntsman, for example, has been the industry's preeminent specialty chemicals manufacturer. Almost great? Yet even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold. However, the 150,000-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?
Maybe it's a sign of the apocalypse or just that we have been in a speculative bubble that needed bursting, but a company like Under Armour that's been beating estimates and raising guidance -- just not beating by enough or raising forecasts enough, apparently -- keeps getting dropped to the canvas. The athletic apparel maker has beat Wall Street estimates for two consecutive quarters now (and for 10 of the past 11 quarters!), but its stock trades 26% lower than it did beforehand.

That lower valuation is attracting CAPS members like shawnd777, who believes Under Armour makes a better-quality product than Nike (NYSE:NKE):

I have been watching UA sales grow in front of my eyes the last 3 years. I didn't realize that they were a publicly traded company until recently. These guys have a product that is higher quality than NIKE, which IMHO is becoming synonomous with cheaply made product using child labor. What finally made me pull the trigger is when my co-worker (a high level attorney at our large tech company in silicon valley) came into the office with a really nice Polo shirt - you guessed it - made by UA! I have some of their products but I will be using the profits from this purchase to finance my wardrobe and my retiremen well into the future. STRONG Sales & rev growth and attractive PEG ratio.

Not everyone sees it that way. CAPS member bobbyabull says the brand has cachet, but is not particularly cheap based on a host of metrics:

Cool 'new kid on the block' brand; hip logo & name BUT they just said they expect to earn $1.02 per share in 2010. With a 5% profit margin, expected growth in earnings of 20% over the next 5 years and no dividend - isn't a P/E of 25 enough? I just don't see the upside from here. Wait until UA drops below $20, then pounce...

We'll have to wait for the annual report, but based on trailing numbers Under Armour has an enterprise value that trades at more than 17 times its free-cash-flow-generating capabilities, making it not overly expensive but not a bargain-basement value either. In comparison, Nike trades at 13 times its cash flow and Columbia Sportswear (NASDAQ:COLM) at a miniscule 6 times.

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.

Cypress Semiconductor and Under Armour are Motley Fool Rule Breakers picks. Columbia Sportswear and Under Armour are Motley Fool Hidden Gems picks. The Fool owns shares of Under Armour. Try any of our Foolish newsletter services today, 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 here. The Motley Fool has a gold-plated disclosure policy.