For some investment industry veterans, seeing Google ( GOOG) shares top $400 brings back memories -- bad ones -- of stocks that have fallen from grace.

During the 1960s, stocks such as Xerox ( XRX), IBM ( IBM) and Polaroid were all the rage, selling at multiples as high as 100 times earnings -- even higher that where Mountain View, Calif.-based Google trades today.

"I saw them all go to less than 10 times earnings," said Don Hodges, a 30-year veteran of the investment world who oversees $215 million in assets for First Dallas Securities, which doesn't own Google shares. "I couldn't see putting a big position into Google."

On the basis of estimates compiled by Thomson First Call, Google's stock currently trades at 69 times the consensus earnings view for the year ending next month. Using the 2006 estimate, the multiple is about 48.

Like those former highfliers, Google, too, will eventually fall from its lofty valuation, these seasoned pros say, though they admit they have no indication that the search engine giant's business is showing signs of faltering. Rather, they base their skepticism on seeing other once-beloved stocks fall out of favor -- a pattern that they expect to repeat itself with Google.

"When that happens, Google is going to get creamed," said Chuck Hill, another longtime investment veteran and the head of the research firm Vertias Et Lux. "It will probably get creamed too much. At this stage, the easy money has been made."

Hill, who said he would advise people to sell their Google shares ahead of a market correction he sees coming next year, dates his skepticism to when he wrote his master's thesis at Harvard. He argued at that time that the then-popular optical character recognition companies weren't good investments because of the competition from IBM. His thesis proved to be correct.

To be sure, Google's appeal is undeniable. Its shares have risen more than 350% since going public last year. And Wall Street analysts are predicting that the company will have better revenue growth in the fourth quarter than other tech giants, including its rivals Yahoo! ( YHOO) and Microsoft ( MSFT).

Because of its embrace by investors, Google, which was founded seven years ago, now has a market valuation of $112.7 billion, surpassing the $109 billion value of tech bellwether Cisco Systems ( CSCO) and the $58.7 billion market value of Motorola ( MOT). Even more remarkable: Google's market cap is creeping close to those of 88-year-old IBM and 168-year-old Procter & Gamble ( PG).

Google has beaten Wall Street estimates for three straight quarters. Analysts' profit estimates for the fourth quarter range from $1.48 to $1.91 with sales seen between $1.15 billion and $1.91 billion. Yearly forecasts range between $5.39 and $6.18 with sales expected at $4.07 billion to $6.13 billion, according to Thomson Financial.

The wide range of estimates, coupled with Google's short operating history, make it difficult for investors to figure out if the company's shares are fairly priced.

"It's an intriguing company, but I don't know how to value this kind of company," said Hodges of First Dallas Securities. "Its obviously selling on promise, and their history is so short that you really can't make too many assumptions about."

Google's rise also brings back memories for George Schwartz, president of Bloomfield Hills, Mich.-based Schwartz Investment Counsel, of other booming companies that investors pinned their hopes on, only to be disappointed.

"There's always been cycles for mania," said Schwartz, adding that it's part of human nature. "People want something for nothing."

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