(A digest of investment opinion from the world's leading financial advisers)

A defined-contribution retirement plan like a 401(k) should offer its participants well-managed, low-cost mutual funds they can depend on for years to come. Most 401(k) participants want broad diversification that will tone down the effects of sell-offs yet provide exposure to rallies. They also want funds that are easy to use. And they shouldn't have all their eggs in one basket either, says Morningstar Mutuals, the leading fund advisory service.

"All 401(k)s should diversify among fund companies because similar problems can often hit many or all of the funds in any one firm. Consider, for example, the dismal performance of Putnam's growth funds in the most recent bear market. The problem there was a combination of poor research and poor risk controls throughout the firm. We've also seen firms hurt by mass defections of managers, bad market timing and other calamities."

The difference between building a regular fund portfolio and selecting a 401(k) lineup, says Morningstar, is that with the latter you want to build in some overlap so you have multiple options when choosing funds, whereas there's not much point holding redundant funds in a regular portfolio.

With that caution in mind, here are the pure stock funds Morningstar has chosen for its own company 401(k), along with its capsule description of each.

LARGE-CAP FUNDS: