Stocks have had a marvelous run. The Dow Jones industrial average continued to set records last week, while the Standard & Poor's 500 hit its highest level since September 2000, coming a hair's breadth from a new peak.

It vindicates investors who stuck with stocks during the crash early in the decade. But it's important not to fixate on these two gauges, and I'll talk about a range of investment options, from other classes of stocks to bonds and bank accounts, in a moment.

Because most pros use the S&P 500 to gauge the broad market, let's see how it has held up. It contains the 500 largest U.S. stocks, with market capitalizations (share price times number of shares outstanding) of at least $4 billion each. I look at the index mutual funds that invest in the S&P 500 stocks because they show what investors can actually make once investment costs are counted.

So far this year, these funds were up 6.35 percent through Thursday, according to Lipper, the tracking firm. They've gained 16 percent in the last 12 months and averaged about 8 percent a year over the last 5 years.

That's good. The five-year figure is a tad short of the long-term average of 10 percent or 11 percent, but it still makes stocks the best long-term investment because it beats bonds and cash by a wide margin.

But if you want to find some really big winners, you need to look at other categories that belong in a well-diversified portfolio.

One is "mid-cap" funds, containing stocks with market caps of $1 billion to $4.5 billion. These are up more than 10 percent this year and more than 12 percent for the last 52 weeks, and they've averaged 11 percent a year during the last five years.

That's terrific. Although there's no guarantee that this will continue, some pros think mid-caps now are a sweet spot that can beat bigger stocks without the sharp ups and downs found with smaller ones.

Small-stock funds, with market caps of $300 million to $1.5 billion, are up about 7 percent this year, nearly 8 percent for the last 12 months, and an average of more than 11 percent a year for the last five years.

Now, if you want to find some really, really big winners, look to more specialized funds. Those limited to natural resources stocks and utilities stocks are up about 14 percent this year, largely because of increasing energy prices.

Should you invest in them? Well, don't bet the farm. These stocks are volatile, and I'd worry about getting into a hot sector too late, then riding a downturn.

Many foreign-stock funds have done very well, too. The average is up about 8.5 percent this year and 15.7 percent for the last 12 months. They've averaged 17 percent a year for the last five years, and many experts say Americans should have 20 percent to 40 percent of their stock portfolios in foreign stocks.

But be prepared for some heart-wrenching downturns - foreign stocks are for the long run. Rather than betting on single markets such as Japan or China, get a broadly diversified fund that invests in many countries.

You can search for them - and for the other categories of funds mentioned here - at www.morningstar.com. That site also has tools for figuring how much of a portfolio should be allocated to each type of investment. Most brokerages and fund companies have similar calculators on their sites.

Long-term investing also means owning bonds, which also is most easily done through mutual funds. Bonds don't generally return as much as stocks do over the long run, but they help stabilize a portfolio because they may do well when stocks are falling.

Funds holding U.S. government bonds are up about 1.5 percent this year and have averaged 3.8 percent a year over the last five years.

If you're putting new money into bond funds now, consider ones with average maturities of five years or less - perhaps even two years or less.

That's because we're in a fairly unusual period when interest rates, or yields, on short-term bonds are just as good as those on long-term bonds, which don't mature (return the investor's principal) for 10 to 30 years.

If prevailing interest rates come down over the next year or two, long-term bonds paying less could lose a lot of value, while short-term ones would hold up. Why risk a loss in long-term bonds if interest rates are just as high on short-term ones?

In fact, if an asset-allocation calculator suggests you own bonds, think about investing in bank certificates of deposit, instead. The best one-year CDs pay about 5 percent, and the federal government insures that you won't lose your principal. Shop for CDs at www. bankrate.com.