Do you suffer from portfolio envy? Do you see a stock such as Mosaic (NYSE: MOS), which appreciated more than 300% in 2007, and kick yourself because it wasn't in your portfolio? Do you think of, up more than 130% in 2007, and wonder why you didn't invest in it?

Well, calm down. There's a simple reason why you never found these stocks: You don't spend most of each day studying the stock market. You don't scour annual reports and financial filings for a living. You don't crunch stock numbers regularly. You are a regular person with a regular life.

But wait!
Fortunately, being a regular person with a regular life doesn't mean you're out of luck. You have options. One good option I'm relying on more and more these days is mutual funds. By doing so, I'm letting skilled professionals choose the most promising stocks they can find for my investments. And better still, they decide when to buy and when to sell, sparing me from having to keep up with lots of companies.

Look at the CGM Focus (CGMFX) mutual fund, for example. According to Yahoo! Finance, the fund owns roughly 1% of Mosaic, making it the third-largest fund holder of the stock. It also sports, among its recent top holdings, shares of Freeport-McMoRan Copper & Gold  (NYSE: FCX) (up 87% in 2007), Posco (NYSE: PKX) (up 82%), and Potash (NYSE: POT) (up 200%-plus).

The fund with the biggest chunk of is Legg Mason Value Trust (LMVTX), which owns more than 4% of the company. The fund's top holdings recently included Time Warner (NYSE: TWX), General Electric (NYSE: GE), and Qwest Communications (NYSE: Q).

The downside
So should you snap up shares of these funds as soon as you can get to your checkbook? Not necessarily. For one thing, CGM Focus' amazing average is boosted by an exceptional year -- it gained roughly 80% in 2007, a feat that will be hard to repeat. Meanwhile, the Legg Mason fund has struggled in recent years, lagging the market. Remember that just because a fund owns a lot of a super performer, that doesn't mean its other holdings are similarly golden. You need to be picky when choosing funds. You want ones with low fees and smart managers with impressive track records and philosophies you admire. Ideally, you want no load fees and low turnover in the fund.

The majority of managed mutual funds out there actually underperform the market. So be choosy -- you want only the most promising funds you can find.

The upside
Fortunately, it is possible to find such funds. You can do so yourself, perhaps by starting at and doing a lot of digging. Here's another approach I recommend (because I do it myself): Check out our Motley Fool Champion Funds newsletter. It arrives each month laden with mutual fund recommendations and updates and it even educates you along the way. You can try it out for free for 30 days, during which time you'll have full access to all past issues, so you can read about every recommendation in detail -- with no obligation.

This article was originally published on Dec. 4, 2007. It has been updated. 

Longtime Fool contributor Selena Maranjian owns shares of Time Warner and General Electric. Posco is a Motley Fool Income Investor recommendation. Amazon and Time Warner are Motley Fool Stock Advisor recommendations. CGM Focus is a Motley Fool Champion Funds recommendation. The Motley Fool isFools writing for Fools.