Welcome back to the world of the Cash Kings, where we highlight businesses that generate a healthy dose of free cash flow. Why is cash flow so important? Because it gives management the opportunity to boost shareholder value through actions like:

A Fool's guide to free cash
Investing, after all, is about putting money up front today to get more of it in return tomorrow. Here at the Fool, we're firm believers that free cash flow, as opposed to traditional accounting earnings, is the best gauge of a firm's health and profitability (or lack thereof).

So, with these cash flow lessons deeply ingrained in your Foolish subconscious -- or maybe just bookmarked as a favorites page -- I'll highlight three more cash-flow rulers of our Motley Fool CAPS kingdom.

Unlike Medis Technologies (NASDAQ:MDTL) -- which is a cash-burning company that CAPS overwhelmingly dislikes -- these are businesses with free cash flow-to-sales margins of 15% or more (also known as the Cash King Margin) that our community is pretty bullish about.

So, sound the trumpets! Here's another trio of cash kings from CAPS:

Company

Cash King Margin (trailing 12 months)

CAPS Bulls

CAPS Bears

Canadian National Railway (NYSE:CNI)

21%

152

2

Infosys Technologies (NASDAQ:INFY)

16%

590

12

Blue Nile (NASDAQ:NILE)

15%

443

67

As always, don't consider these stocks formal picks, but rather suggestions worth further investigation. After all, due diligence is the Fool's way to riches.

But just for starters, here's a quick summary of these cash-throwing kings, and how some of their loyal CAPS followers feel about them.

Ruling the rails          
With a whopping free cash flow-to-sales margin of more than 20%, Canadian National Railway takes the honors as this week's most prolific cash king. As arguably the most efficient railroad operator in the world, CN Rail has the cross-continental route system (linking customers in Canada, the U.S., and Mexico), industry-standard "on-time" service, and growth opportunities from the rise of international trade to keep its freight cars filled with cash.

In addition, CAPS All-Star jrerickson003 says that intense cost pressures in the transportation industry will only work in CN Rail's favor over the long and lengthy haul:

Railroads will have a sustainable competitive advantage over trucking in the foreseeable future due to high fuel costs and hiring problems facing trucking companies. These issues will not go away anytime soon. CNI is the most efficient operator in the industry and benefits from transporting all the goods traveling from Asia to Canada's Western coast.

Bangalore lore
The next monarch on our list is India-based Infosys Technologies, one of the world's largest and most esteemed IT service providers. For more than two decades, Infosys has utilized labor-cost advantages, a massive global client base, and a disciplined delivery process to generate healthy and predictable cash flows.

Thanks to a strong competitive position and continued expansion worldwide, CAPS player djgardner31 thinks Infosys is poised to keep on delivering:

"No longer thought of as 'that Indian firm,' they are a major player in the worldwide services/outsourcing market, and will continue to win against players such as Accenture (NYSE:ACN) and IBM in rapidly developing Asia due to cost structures. Their footprint in the U.S. and Europe also continues to grow."

King of the Nile
Our last free cash flow king this week is Blue Nile, the largest online retailer of certified diamonds and jewelry. Blue Nile's rock-solid reputation for rocks, coupled with its consumer-direct business model -- which gives it the cost edge over names like Tiffany (NYSE:TIF) and Amazon (NASDAQ:AMZN) -- have made it a two-time selection of our Motley Fool Rule Breakers service. The stock is up 88% and 56% on the first and second recommendations, respectively.    

Our very own CAPS All-Star TMFLomax elaborates on why Blue Nile has been, and should continue to be, a sparkling investment:

With no bricks-and-mortar stores, there's no hard sell or distraction or snobby salespeople, and Blue Nile's site focuses on customer education on diamonds. They did a great job of creating a well-known Internet brand in very little time. ... Management also seems to be smart and honest. A great stock for the long term.

The Foolish bottom line
Free cash flow-generating companies like CN Rail, Infosys, and Blue Nile are always among my top candidates to research further. Our Motley Fool CAPS intelligence database is a great place to look for your own cash kings or read how your fellow Fools feel about thousands of different stocks.

Click here to join the forward-thinking CAPS community free of charge.

Be sure to join us next time, when I'll feature three more cash kings from CAPS. Until then, may your cash flow reign supreme.   

For more Foolish usage of free cash:

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Blue Nile is a Motley Fool Hidden Gems and Rule Breakers recommendation. Accenture is an Inside Value selection, and Amazon is a Stock Advisor pick. The Fool's disclosure policy is the strict set of rules that always rules Fools.