"Don't catch a falling knife," as the old saw commands. (Pardon my mixing a cutlery metaphor.) The idea of buying a former superstar stock at a discount price certainly has its attractions, but you've got to make sure you catch the haft -- not the blade. That's where Motley Fool CAPS comes in.

Today, we once again stand beneath Mr. Market's silverware drawer, measuring which knives have fallen the farthest. Then we'll call on CAPS to ask which of these stocks -- if any -- Foolish investors believe are ready for a rebound. Let's meet today's list of contenders, drawn from the latest "52-Week Lows" list at WSJ.com:

Company

52-Week
High

Recent
Price

CAPS Rating
(5 stars max.)

BB&T (NYSE:BBT)

$45.31

$15.33

**

Interface (NASDAQ:IFSIA)

$18.00

$3.48

****

International Bancshares  (NASDAQ:IBOC)

$35.80

$14.98

****

PPG Industries  (NYSE:PPG)

$69.89

$36.21

***

Under Armour (NYSE:UA)

$44.00

$15.82

***

Companies are selected from the "New Highs & Lows" list published on WSJ.com on the Saturday following close of trading last week. 52-week high and recent price provided by Yahoo! Finance. CAPS ratings from Motley Fool CAPS.

Knives and knaves
If there's one good thing about a broad-based market sell-off, it's that you find a lot of terrific companies getting the ol' baby-and-bathwater treatment. Tossed out on their rosy little bums as if they were bums of another sort. You just know that some of these babies are gonna bounce right back once the suds subside.

But as it turns out, The Motley Fool has already adopted a lot of these babies. Under Armour and International Bancshares are fine ideas -- but they're also existing Motley Fool Hidden Gems picks. PPG Industries and BB&T? Again, old hat. Both are Income Investor selections. And of course, Under Armour is also a Rule Breakers pick. Is there anything new under the sun? Read on as we discover...

The bull case for Interface
CAPS newcomer jwalsh71 introduced us to Interface last summer:

First, Ray Anderson ... has provided a genuine vision for many other businesses to follow ... While recycling carpet may not sound too exciting, businesses like Interface will begin to lead the pack as the mental shift to going green really starts to take hold. ... As oil prices rise due to increasing global demand, alternative carpet production techniques need to be used to offset the rise in the raw petroleum input costs for carpet. And Interface is already doing this by using recycled carpet as fuel for the process.

CAPS All-Star luckybunni agrees. Writing in May: "Interface is ... looking toward a future where oil products will be rare or non-existent. FLOR is a fashionable, sustainable, quality product that will pave the way for the future of carpet. I've notice that Target [ (NYSE:TGT)] has recently began stocking FLOR tiles." (And Lowe's (NYSE:LOW) has got 'em, too.)

In October, akmarker added that:

Interface has several long-term programs going that should bear fruit over the next several years. They've captured the value of ... operational efficiency measures and now are moving on toward reducing their energy consumption and environmental footprints. In the short term these efforts tend to absorb cash, but I expect that over the next 10 years we'll see some strong payoffs.

Ah, but in a market that asks only "what have you done for me lately" -- and defines "lately" as "within the last three months" -- will investors be willing to wait 10 years? More importantly, should you?

The answer really depends on how much faith you put in GAAP accounting standards. You see, from a surface-level viewpoint, Interface isn't just a bargain -- it's a steal. The stock trades for less than a P/E of 4, yet despite the recession, Wall Street analysts expect this company to grow its profits at 15% per year over the next half-decade. That looks cheap. Problem is, it's probably too good to be true.

Dig a little deeper, and you'll find that beneath Interface's lush, shag surface lies a bare $25 million in free cash flow for the last 12 months -- too little to support even half of Interface's reported net profit. And as for the "P" part of the P/E equation, it doesn't incorporate the firm's $225 million in net debt. Tack that debt on to the market cap, and you're looking at a business valued at roughly 18x its free cash flow. Pretty pricey, in light of the limited growth prospects.

Time to chime in
Now, maybe I'm being too pessimistic. Maybe we will run out of oil in the next 10 years, Interface will become known as the visionary "Microsoft of floor coverings," its profits will surge past all expectations, etc. and so on. But I'm not holding my breath. Neither should you.

Literally. As in -- even if you disagree with me, don't hold back. We're equal opportunity arguers here at the Fool, and if you've got an argument in Interface's favor, we've got a place to tell it. Click on over to Motley Fool CAPS and give us a shout.

Motley Fool CAPS : It's fun, it's free, and it just might make you famous. 

Under Armour and International Bancshares are Motley Fool Hidden Gems picks. PPG Industries and BB & T are Income Investor selections. Under Armour is a Rule Breakers pick. Microsoft is an Inside Value selection. The Fool owns shares of Under Armour.

Fool contributor Rich Smith does not own shares of any company named above. You can find him on CAPS, publicly pontificating under the handle TMFDitty, where he's currently ranked No. 506 out of more than 125,000 members. The Fool has a disclosure policy.