There are many ways to value a company. Price to earnings. Price to cash flow. Liquidation value. Price per eyeballs on website. Price to a number I made up (this one never gets old). Price to CEO's ego divided by lobbying activity as a percentage of revenue (this one doesn't get used enough).

Which one is best? They're all limited and reliant on assumptions. No single metric holds everything you need to know.

The metric I'm using today is no different. But it's perhaps the most encompassing, and least susceptible to hidden complexities of a company's financial statements. The more I think about it, the more I feel it's one of the most useful metrics out there.

What is it? Enterprise value over unlevered free cash flow.                                                       

• Enterprise value is market capitalization (share price times shares outstanding) plus total debt and minority interests, minus cash.
• Unlevered cash flow is free cash flow with interest paid on outstanding debt added back in.

The ratio of these two statistics provides a valuation metric that takes into consideration all providers of capital -- both stockholders and bondholders.

But you invest in common stock, so why should you care about bondholders? Ask Lehman Brothers investors why. When a company earns money, it has to take care of bondholders before you, the common shareholder, get a dime. Focusing solely on profits and equity can be misleading.

Enterprise value provides a more encompassing view. By bringing debt capital into the situation, we see real earnings in relation to the company's entire capital structure. If you owned the entire business, this is the metric you'd naturally gravitate toward.

Using this metric, here are five companies I found that look attractive.

Source: S&P Capital IQ.

Let's say a few words about these companies.

Three years ago, Warren Buffett and Charlie Munger had some flattering words for Google. "Google has a huge new moat. In fact I've probably never seen such a wide moat." Munger said. "I don't know how to take it away from them," Buffett said. "Their moat is filled with sharks!" Munger added.

Here's a good example: After trying to make inroads in the online ad business, Microsoft just wrote down almost the entire value of its 2007 purchase of aQuantive. The Daily Beast summed it up well: "Microsoft's $6.2 Billion Writedown Shows It's Losing War With Google."

I still like Microsoft because it's good at what it does. But advertising and search isn't it. That's Google's turf. And today you can buy Google at literally the lowest price-to-cash-flow ratio ever. Take advantage of that while it lasts.

Johnson & Johnson is one of the best-performing stocks over the last several decades. But it's having a rough go of it lately. Recalls, management blunders, more recalls, competition from generics... and on and on. Yes, growth has slowed. Yes, it might stay slow for a while. But valuation more than compensates for that. The stock currently provides a 3.6% dividend yield, and trades for 12 times next year's earnings -- below the market average. It's a good company at a good price.

Procter & Gamble is a similar story. One of the world's greatest collections of brands has hit a slowdown. That's hit shareholder returns -- P&G shares haven't budged in two years. But most of the company's missteps appear to be tied to poor execution by management. My guess: Within a year or two the company will have a new CEO, and the market will come to appreciate its value anew.

Everything important you need to know about UnitedHealth Group comes down to the Affordable Care Act, also known as Obamacare. Most health insurance companies currently trade at depressed valuations, likely because the market hates uncertainty -- something that still exists even after the Supreme Court ruled Obamacare constitutional.

But what are the two most likely outcomes here? One is that Obamacare remains law, in which case insurers will face a raft of costly new rules, but also a flood of new customers essentially mandated to buy their product. The other is that Obamacare is repealed -- likely under a Romney administration -- in which case those costly new rules would go away. Neither outcome seems particularly bad for insurers.

Past performance is no guarantee of future returns, but I can't help but point out how successful Colgate-Palmolive has been over the last 30 years. The toothpaste and soap company has produced average returns of nearly 17% a year since 1980, compared with 11% for the broader market. That's the power of two forces: A strong brand, and simple products that aren't pushed to extinction by new technology. Combine that with a pretty reasonable valuation, and Colgate-Palmolive should be a great company to own for years to come.

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