LONDON -- The stock market, it's fair to say, is in an uncertain mood. As in the early days of 2009, just before the market's nadir, daily items of news are having a disproportionate effect on sentiment. The economy, Greece, banking downgrades, American purchasing and housing surveys -- you name it, and stock prices are reacting to it, oscillating wildly from euphoria to gloom.

At such times, it's tempting to sit it out and wait for a calm before putting more money into the market. But that, I think, would be a mistake.

Here's why.

Pessimism abounds
Let's start with why the market is reacting to news and not shrugging it off. Simply put, investors today are far more pessimistic than they were earlier in the year, when the FTSE 100 (INDEX: ^FTSE) was within a few points of 6,000.

And pessimistic markets, in short, are buying opportunities. As Benjamin Graham put it, "Buy when most people -- including experts -- are pessimistic, and sell when they are actively optimistic." Or, to cite that other well-known super-investor, Warren Buffett: "Be fearful when others are greedy, and be greedy when others are fearful."

Can the market get more pessimistic still? Undoubtedly. Can people become even more fearful? Of course. But with the market down 10% to 15%, you can buy today the same shares you were buying just weeks ago -- but significantly more cheaply.

And, as Warren Buffett so memorably put it in a thoughtful article in Fortune magazine a few years back:

When hamburgers go down in price, we sing the Hallelujah Chorus in the Buffett household. When hamburgers go up, we weep. For most people, it's the same way with everything in life they will be buying ‑‑ except stocks. When stocks go down and you can get more for your money, people don't like them anymore.

And the stock market's hamburgers have unquestionably gone down in price. Take AstraZeneca, Aviva, BT, BAE Systems, Barclays, and Lloyds Banking Group; undeniably, Britain's blue chips have gone on sale.

That said, only some of those particular blue chips are rated as a "buy" by Neil Woodford, the subject of a recent special free Motley Fool report: "8 Shares Held By Britain's Super Investor." And others in that short list above, it's fair to say, he wouldn't touch at all. Which are which? Why not download the report and find out? As I say, it's free.

Asset class perspective
That said, it's possible to view today's market in a very different light. Namely, this way: If you don't like shares at today's prices, what do you like?

Cash? Real returns are either negative or zero -- and the next move in interest rates is likely to be downward. Property? You're braver than I am. Gilts? Every bubble has to burst one day -- and we're surely in a gilt bubble. And so on.

On the other hand, decent blue chips are on yields of 5% or so, delivering dividend growth of 5% to 10%, and they offer capital growth into the bargain -- at very reasonable prices, no less. The FTSE 100's price-to-earnings ratio yesterday was 9.88, compared with 19.88 10 years ago -- and that, in short, is one helluva difference in valuation.

Watchlist wonders
Frankly, there's not much point in having a watchlist if all you do is, well, watch it.

Or, as master investor and economist John Maynard Keynes so memorably didn't quite say: "When shares on my watchlist scream 'bargain,' I buy them. What do you do, Sir?"

And with those sentiments in mind, there's one share in particular that I've been loading up on in recent times, having almost doubled my holding this year. What's more, I'll be buying still more of it in mid-July, when I've banked my dividends from Sainsbury, Marks & Spencer, GlaxoSmithKline, and BP and found some more spare cash.

Its name? You can find that out in another free special report from The Motley Fool: "The One UK Share That Warren Buffett Loves." From the way Buffett has seemingly been topping up himself in recent times, it's clear that the share is on his watchlist, too. The report is free, so why not download a copy now?

Your view?
Of course, not everyone will agree with me. Some of you -- as you've explained before in comments appended to articles like this -- are rather keener on property than I am.

But with the FTSE 100 on a P/E below 10, real interest rates largely negative, and a wobbly housing market, that's the world as I see it. Comments? That's what the box below is for.

Are you looking to profit from this uncertain economy? "Ten Steps To Making A Million In The Market" is the very latest Motley Fool guide to help Britain invest. Better. We urge you to read the report today -- it's free.

More investing ideas from Malcolm Wheatley:

Malcolm owns AstraZeneca, Aviva, BT, BAE Systems, Lloyds, Sainsbury, Marks & Spencer, and GlaxoSmithKline. He doesn't have an interest in any other shares listed. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.