"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 have 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 to measure 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 "New 52-Week Lows" list on WSJ.com:

Stock

52-Week High

Recent Price

CAPS Rating (5 Max):

Spirit AeroSystems  (NYSE:SPR)

$36.22

$7.80

*****

Blackstone Group  (NYSE:BX)

$24.26

$4.65

**

Pulte Homes  (NYSE:PHM)

$17.32

$7.12

*

KB Home  (NYSE:KBH)

$28.99

$8.02

*

SunTrust Banks  (NYSE:STI)

$73.34

$22.45

*

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

Knives and knaves
By close of trading Friday, 377 stocks on the tech-heavy Nasdaq -- nearly one stock in eight -- crashed through the floor to end at their lowest prices in 52 weeks. The more staid NYSE fared better, but not by much. There, "only" one stock in 14 had its worst day in a year, as 290 new lows were set.

But here's the good news: Some of the best-performing stocks of the recent housing boom can now be had for pennies on the few-years-ago dollar. Star homebuilder Pulte and still-profitable southern banker SunTrust are all selling for what would have seemed pipe-dream prices just a couple of years back.

Granted, judging from the ratings above, few investors would dream of shelling out good money for most of these stocks today. But there's at least one 52-week loser that they think worth the price of admission. Airplane-parts maker Spirit AeroSystems' products can be found in everything from General Dynamics' (NYSE:GD) Gulfstream business jets all the way up to Boeing's (NYSE:BA) long-awaited 787 Dreamliner. And as our CAPS members are about to tell us, that's a good thing indeed.

The bull case for Spirit AeroSystems
As dlanka pointed out last summer, there aren't "a lot of companies doing what [Spirit Aero] does, plus their goal is to be the low-cost provider of choice for aircraft replacement parts." Our CAPS All-Star continued: "As Fletch once said, 'It's all ball bearings these days.'"

Yet Valuevest observed earlier this year that Spirit's "price is hurt by delays in A380 and 787, both of which rely on [S]pirit as a major supplier. As soon as one or both of those ramp up production, [Spirit Aero] should go thru the roof."

Another CAPS All-Star, SlowThought, looks at the stock and muses:

With a book value of $10/share, I can't see any significant downside. Short term, when BA resolves the strike, [Spirit Aero] will get significant pin action. Long term, as a supplier of [Boeing] and EADS, with the entire commercial airline fleet facing replacement over the next 10-15 years, what's not to like?

Although SlowThought's question sounds rhetorical, I'll volunteer the obvious answer: Boeing's strike has ended (and a second strike averted), yet Spirit's stock price is still down. But is this cause for disappointment at a failed investment thesis ... or for rejoicing that there's still time to get in on this "pin action" that Valuevest discussed?

For what it's worth, here's how I look at the situation: Spirit looks cheap. Amazingly, incomprehensibly, crazy cheap. I mean, the stock trades for a price-to-earnings ratio of 3 -- both trailing and forward -- which is less than half of Boeing's own also-cheap-seeming P/E of 7.

But when comparing the two, I still prefer Boeing over Spirit. Why? For one thing, Spirit carries quite a bit of debt, while Boeing has cash in the bank. For another, Spirit hasn't generated a penny of free cash flow in three years, while Boeing has generated nothing but positive free cash flow for 15 years running.

Time to chime in
Now, that doesn't mean Spirit's not a bargain, too. In fact, trading below book value as it does, Spirit is probably every bit the bargain that our CAPS members perceive. All I'm saying is that I think Boeing's the better deal -- which is why I own a stake. But you're free to disagree on the point.

In fact, if you do disagree, how 'bout you come on over to Motley Fool CAPS and tell us why?

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

Fool contributor Rich Smith owns shares of Boeing. You can find him on CAPS, pontificating under the handle TMFDitty, where he's ranked No. 917 out of more than 120,000 players. The Fool has a disclosure policy.