Hard to believe that WilliamsCompanies (NYSE:WMB) was flirting with oblivion only three and a half years ago. Whacked by the confluence of the Enron collapse and an ill-fated overexpansion into fiber optics and energy trading, this company got quite a bit closer to the brink than most investors would ever like to see.

But that's then, and this is now. The company is now focused almost entirely on natural gas, and the stock price has recovered significantly. And while management's earnings guidance wasn't exemplary, this may yet prove to be a company worth watching.

There are plenty of ways to evaluate Williams' performance, but I prefer to go with earnings from continuing operations (including mark-to-market adjustments) and operating cash flow. By those standards, the performance was mixed. Earnings roughly tripled from last year's fourth quarter, but full-year operating cash flow was actually down slightly (about 3%).

Performance was pretty good in the exploration and production business, although hedges did prevent the company from capturing all of the increase in natural gas prices. Volumes were up 14% in the quarter, the reserve replacement for the year was 277%, and the company has aggressive plans for drilling and production in 2006. In other business, including midstream operations and pipeline, the performance was not so stellar, although I believe that these franchises remain valuable.

Part of the trick here is that Williams is probably more attractive as a whole than it is in pieces. In other words, you can find better natural gas E&P companies (like Chesapeake (NYSE:CHK) or XTO (NYSE:XTO)), and better midstream and pipeline companies (like EnterpriseProducts (NYSE:EPD) and Kinder Morgan (NYSE:KMI)). But there aren't too many soup-to-nuts natural gas plays like Williams that have all of those businesses.

While the company's considerable debt load is a reason for caution, this may yet be an interesting idea for some investors. The fast-growing E&P business gives you some upside to the current energy upswing, while the midstream and pipeline business are more stable cash-generating enterprises. Although not necessarily best of breed, Williams Companies is still no mutt.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).