Warren Buffett

Here's the latest Chairman's Letter from Berkshire Hathaway: pdf link. Have a read.

And a key section (from page 6):

Businesses – The Great, the Good and the Gruesome
Let’s take a look at what kind of businesses turn us on. And while we’re at it, let’s also discuss what we wish to avoid.

Charlie and I look for companies that have a) a business we understand; b) favorable long-term economics; c) able and trustworthy management; and d) a sensible price tag. We like to buy the whole business or, if management is our partner, at least 80%. When control-type purchases of quality aren’t available, though, we are also happy to simply buy small portions of great businesses by way of stockmarket purchases. It’s better to have a part interest in the Hope Diamond than to own all of a rhinestone.

A truly great business must have an enduring “moat” that protects excellent returns on invested capital. The dynamics of capitalism guarantee that competitors will repeatedly assault any business
“castle” that is earning high returns. Therefore a formidable barrier such as a company’s being the lowcost producer (GEICO, Costco) or possessing a powerful world-wide brand (Coca-Cola, Gillette, American Express) is essential for sustained success. Business history is filled with “Roman Candles,” companies
whose moats proved illusory and were soon crossed.

* Photo taken from JasonSmith's public flickr stream. Original photo found here.