His contributions to the investment world are pretty slim, but when baseball great Yogi Berra quipped that "the future ain't what it used to be," he might as well have been referring to the Wall Street panic of 2008.

There's a tremendous difference between a company that's cyclically impaired vs. a company in the middle of a paradigm shift. After all, General Motors was once an innovation heavyweight; Kodak used to be second to none; and Enron was one of the "most admired companies" named by Fortune magazine. Things change. Quickly.

Today I'm going to take a look at seven companies that may have sat atop the "safe stocks you'd recommend to grandma" list earlier this year, but could now be facing game-changing headwinds casting their future in doubt. Have a look, and don't forget to vote in the poll below for the safest stock that isn't anymore.

General Electric (NYSE:GE)

  • What made it safe: Bluest of the blue chips. Member of the Dow Jones Industrial Average since 1896. One of the strongest brand names in the world. Has Warren Buffett's approval.
  • What makes it not: In theory, it's diversified. In reality, more than half of profits came from a finance unit that's bound to become a fraction of its former self.

Sears Holdings (NASDAQ:SHLD)

  • What made it safe: Chaired by billionaire investor and Warren Buffett disciple Eddie Lampert. One of the more successful turnaround stories of all time. Has the blessing of other highly respected value investors. Potential real estate gold mine.
  • What makes it not: It's retail. Lampert spent a gazillion dollars buying back shares when the stock was multiple times higher than today's price. Too much focus on milking cash out of the company led to an ignorance of capital improvements and dilapidated stores. Potential real estate gold mine now worth substantially less.

Starbucks (NASDAQ:SBUX)

  • What made it safe: Convinced consumers that waiting in line for 20 minutes to pay $4.95 for a cup of coffee was a good use of their time and money. Decided that building identical coffee shops within spitting distance of each other wouldn't saturate the market.
  • What makes it not: See above.

American Express (NYSE:AXP)

  • What made it safe: Enormously valuable brand name. Unmatched appeal. The sole choice of anyone looking to turn heads at the cash register. Gives Warren Buffett goose bumps just thinking about it.

Bank of America (NYSE:BAC)

  • What made it safe: Sprawling, nationwide branch network. Enviable deposit base. Stellar management team keen on strategic acquisitions. Unlike rival Citigroup, knows how to grow while keeping complexity in check.
  • What makes it not: It's a bank, duh. Deal to purchase Merrill Lynch for less than a fire-sale price could turn disastrous if the finance world keeps imploding.

ExxonMobil (NASDAQ:XOM)

  • What made it safe: Couldn't go a single quarter without breaking profit records. You know it's good when Congress has to drag in the CEO to explain why the company's making so much money.  
  • What makes it not: Oil is down 70% since July. At least one oil executive says oil could fall to $20 a barrel and gasoline to $1 a gallon in 2009. Could become a poster-child victim of spiraling deflation.

Toyota Motor (NYSE:TM)

  • What made it safe: One of the few auto manufacturers that can produce vehicles without setting piles of cash on fire. Efficient to the extreme. Could seemingly capitalize on increased market share if any of the Big Three go out of business.
  • What makes it not: Sales are still down big time. Could face serious domestic trauma if auto suppliers go belly up from a Big Three collapse. Niche as a supplier of ultra-fuel-efficient vehicles less attractive now that gas is cheap (for the time being).

This is merely a short list, of course. There are plenty of formerly "safe" companies now staring at an entirely different economic landscape.

Any of these formerly beloved names make you queasy? Take a second to weigh in via the Fool poll below and check back to see how your fellow Fools are voting. If you have a candidate not listed here, feel free to put your thoughts in the comment section below.

Fool contributor Morgan Housel doesn't own shares in any company mentioned. Bank of America is a Motley Fool Income Investor pick. Sears Holdings, Starbucks, and American Express are Motley Fool Inside Value picks. Starbucks is a Motley Fool Stock Advisor selection. Get a free 30-day trial subscription to the Fool's investing newsletter services by clicking here. The Fool owns shares of Starbucks and American Express and has a disclosure policy.