The best way to own common stocks is through an index fund.
Here's the logic behind index funds, which aim simply to match the return of a market index: The average fund in any market will always earn that market's return (because in aggregate investors are the market) minus expenses. Since index funds match the market but have much smaller expenses than other funds, they will always beat the average fund in the long run. It's hard to argue with the math, and history bears it out (see the performance stat at right). Besides, if the Greatest Investor of Our Time believes that index funds are superior for most investors, shouldn't you?