NEW YORK (FORTUNE Magazine) - "It takes 20 years to build a reputation, and five minutes to ruin it." The man who coined this aphorism, Warren Buffett, knows a thing or two about great reputations: His company, Berkshire Hathaway, has long been a fixture on our list of America's Most Admired Companies.

In the absence of scandals or financial disasters, the attitudes of corporate leaders toward their competitors tend to shift over years rather than minutes -- but shift they do.

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In the '80s, for instance, respondents seemed to favor large, classic companies like IBM, AT&T, and General Mills.

Then came the age of innovation, which rewarded the likes of Home Depot, Microsoft, Intel, and 3M.

Over the past few years Wal-Mart (Research) and Dell (Research) -- two companies with an obsessive focus on the bottom line -- have made the biggest impression. Each eventually became No. 1 -- Dell in 2005, Wal-Mart in 2004 and 2003.

But this year both those erstwhile leaders got hit. Besieged by criticism and a slumping stock, Wal-Mart tumbled from No. 4 to No. 12.

Slowing growth, missed earnings targets, and a half-billion-dollar write-off for a botched batch of products sent Dell down to No. 8; surprisingly, it didn't make the top half among companies in the computer industry and therefore does not feature in that list at all.

Moving in the other direction, though, were FedEx, Procter & Gamble, and Johnson & Johnson. These three all made substantial jumps in our rankings -- to the No. 2, No. 4, and No. 6 spots, respectively.

What the three new stars have in common -- besides being big and profitable -- is a willingness to chart a course and stick to it, regardless of what competitors, analysts, or know-it-all journalists have to say.

That doesn't mean that Wal-Mart and Dell don't consider the big picture. Of course they do, and that is surely a factor in their staying in the top 15.

But it looks as if this is the year that FedEx, P&G, and J&J are getting rewarded -- at least in terms of recognition from their peers -- for thinking long term and then delivering.

Consider FedEx (Research), which in the third quarter alone launched five new direct flights between Shanghai and Japan, opened a new central China headquarters in Wuhan, signed an agreement to build a giant hub in Guangzhou, opened five branches in southern China, and added the first express delivery service between China and India.

By November the company had 26 air routes in China, and in December, thanks to a new World Trade Organization agreement legalizing the deal, agreed to buy out its Chinese joint venture partner, DTW Group. The sudden flowering of new business was impressive and contributed to a terrific fourth quarter, with more than $8 billion in revenue and a sharply rising stock price. But it was possible only because the carrier had sunk deep roots.

"We've been in China for 22 years," notes Fred Smith, the founder and CEO of FedEx, longer than major rivals like UPS and DHL. "It's a fast-growing market for us now, but it took a lot of hard work and diplomacy to get this far."

Making such strategic inroads in the world's fastest-growing economy puts FedEx in a strong position for the future.

Says Smith: "These kinds of investments never work exactly like you want them to at first. But you can't give up and get risk-averse. You have to keep going."

There is no need to lecture Procter & Gamble (Research) chief A.G. Lafley on how to keep going. He knows the book backwards. In 2005, Lafley put $57 billion of the company's money on the line to buy Gillette. Detractors derided the acquisition as too much for too little, partly because the two companies had to embark on a complicated series of divestitures in order to satisfy antitrust regulators.

Lafley, though, is planning for the next quarter-century, not the next quarter. He sees the merger as a "no-brainer," because buying Gillette dovetails with his long-term strategic goal -- declared in 2000, when he got the top job -- of building the company's billion- dollar brands. Gillette brought five brands worth $1 billion or more to the party, giving P&G a total of 22 billion-dollar babies.

Gillette also gave Procter & Gamble easy entrée to new distribution channels, including drugstores and convenience stores. And P&G can return the favor in China. Gillette was doing pretty well in about 60 Chinese cities, but just four of those accounted for the majority of sales. P&G, meanwhile, sells soap and such in 13,000 Chinese cities and towns. Any doubt that adding thousands of outlets will help Gillette in China?

Johnson & Johnson (Research) had a year to remember, both good and bad. It increased net earnings, to $10.4 billion -- more than double that in 2000 -- but also saw a big deal go south.

For those of our readers who were lost in the Amazon and therefore missed the story, J&J was involved in the biggest, and perhaps the testiest, takeover struggle to date in the medical-devices industry. The short version: Johnson & Johnson offered a premium price for Guidant, a maker of defibrillators and other implantable devices to regulate the human heartbeat, then tried to cut its initial bid by some $4 billion when certain technical problems in Guidant's products came to light. After several more feints and parries, J&J ultimately bowed out in early 2006 to rival bidder Boston Scientific. It wasn't pretty, but J&J had the foresight to negotiate a $705 million breakup fee for the Guidant deal.

"They walked away, and they got $700 million for their trouble," says analyst Matthew Dodds, who follows Johnson & Johnson for Citigroup. "I don't really see a problem here."

The larger point is that despite the brouhaha, the deal that wasn't is a bump in the long road Johnson & Johnson is taking to keep diversifying away from the dicey drug business.

That's still the strategy, and few doubt that Johnson & Johnson will get there. Its Cordis division is already the global leader in coronary stents, and the company plans to continue expanding its sales of medical devices -- in large part by quietly making important acquisitions like its late-2005 purchase of Animas, which makes insulin infusion pumps.

Another poster child for thinking decades down the road, not quarters, is Toyota. The car giant's first exports, in the 1950s, might best be described as Yugos with a Japanese accent. But the company kept improving its products, kept learning, kept making its way into new markets -- and is now on the verge of being the world's biggest car company.

It is already the most valuable, with a market cap ($170 billion) that is 14 times that of GM. One big difference between Toyota and its U.S. competitors: Toyota is formidable outside its home market. Non-Japan sales account for more than two-thirds of the vehicles it sells. Toyota has been running on all cylinders for the past quarter-century and continues to go from strength to strength: That is why, at No. 9, it is the first non-U.S. company to crack the top ten of America's Most Admired list. (It's No. 2 on our global list.)

Of course, exhibit A for the power of positive long-term thinking is GE (Research), which has been doing just that for more than a century. On the current list GE recaptured its standing as America's (and the world's) Most Admired Company. It was also No. 1 from 1998 through 2002.

This year is a particularly strong showing, considering GE's stock has been underwhelming. Poor stock performance does eventually get punished -- witness the disappearance from the list of companies like Rubbermaid, which was No. 1 in both 1994 and 1995 (and bought out in 1999), and Coca-Cola, which led in 1996 and 1997. But clearly our respondents are looking at more than this year's numbers when they record their answers.

The early 21st century has been brutal on corporate reputations. Nevertheless, there are many companies to admire out there. That is why FORTUNE is publishing the top 20 Most Admired Companies, not the top ten, as in previous years. After all, with foreign firms like Toyota cracking the elite, the pool of talent is deeper than ever. A longer list also allows us to recognize rising stars like Apple (No. 11), Costco (No. 15), and the return of an old friend, 3M (No. 20).

If there is one thing that all the Most Admired Companies have in common, it's the ability to change with the times -- and magazine surveys must too.

See the full list of FORTUNE's Most Admired Companies.