It took him long enough.

At the end of 2004, Warren Buffett's Berkshire Hathaway had around $44 billion in cash. Ditto for 2005. And 2006. And, yes, 2007 as well.

At one point, more than 20% of Berkshire's assets were earning money market returns. While armchair investors complained that the company had amassed too much capital to continue its market-thrashing ways, Buffett simply sat on Berkshire's enormous pile of cash. And waited. And waited. And waited some more.

He refused to buyuntil the time was right.

The time is right
Buffett has called the current mess an "economic Pearl Harbor." He's also said, "In my adult lifetime, I don't think I've ever seen people as fearful economically as they are now."

These weren't just words. Mr. Greedy-When-Others-Are-Fearful started stuffing money where his mouth was.

That $44 billion that Berkshire had at the beginning of 2008? By the end of last June, Buffett had spent it down to $31 billion, via deals including Berkshire's purchase of Marmon Holdings, the Mars purchase of Wrigley, and the Dow Chemical takeover of Rohm and Haas. He even bought up auction-rate securities at bargain prices.

And in the second half of the year, he acceleratedthe buying. It's nice to have cash when the credit markets are frozen.

Last fall, Buffett committed:

Buffett was willing to put more than $20 billion to work over that one-month period(although, again, the Constellation deal ultimately fell through). On top of that, he penned a "Buy American" op/ed piece in The New York Times, saying he was putting personal money to work in U.S. equities. Buffett's back, baby!

Buffett's buying. Should you?
Historically, average investors could simply ride Buffett's coattails to returns that easily doubled the market's. But this time is different.

Buffett got sweetheart deals on both Goldman and GE. In the case of GE, he's earning 10% dividends on a company that was AAA-rated at the time. If he buys the warrants and they pan out, he'll earn even more.

When Buffett made those deals, he was providing much more than just capital. He was lending his credibility. That meant Goldman and GE were willing to give him great deals in hopes that his name alone would stabilize their stock prices for follow-on offerings.

In other words, don't buy into Goldman or General Electric just because Buffett has.

Learning from Buffett
Instead of buying what Buffett is buying, we should look to what his strategy has to teach us. So what can we learn from his shopping spree? Two things:

Buffett's pushing 80, but he hasn't been panickingand trying to make a quick buck, no matter what the market has done. Instead, he's been investing for the long term. In the past few years, that's meant waiting for opportunities to present themselves. Now that they are, he's been striking with a vengeance.

Because of his patience, he hasn't had to compromise -- and he's getting great companies at great prices. When Constellation Energy's price dropped so precipitously a year ago (from above $60 to the $20s), he was ready to pounce. Goldman and GE may have approached him, but you can be darn sure that he'd already done the bulk of his research beforehand.

Follow Buffett's lead
To be great investors, we need to be similarly prepared. In volatile times like these, Mr. Market presents us with loads of great values -- but just because a stock price has fallen, that doesn't mean a given company is a good value.

To wit: Here's a screen of companies with market capitalizations above $5 billion that are trading substantially off their 52-week highs:

Company

% of 52-Week High

P/E Ratio

Nokia (NYSE: NOK)

72%

12.5

Monsanto (NYSE: MON)

65%

20.7

Medtronic (NYSE: MDT)

71%

22.2

First Solar (Nasdaq: FSLR) Continued...