Following this model, you could invest your funds in Vanguard Total Stock Market Index Fund and Vanguard Total Bond Market Index Fund.

NPR: Vanguard Founder Advises Riding Out The Storm

Mr. Bogle believes that a simple portfolio including only two funds, the Vanguard Total Stock Market Index Fund and Total Bond Market Index Fund would be sufficient for many investors.

FORBES: Vanguard Founder John C. Bogle -- In Person With The Bogleheads

To show this, I created and rebalanced several portfolios using the Vanguard Total Stock Market Index Fund Admiral Shares (VTSAX) and the Vanguard Total Bond Market Index Fund Admiral Shares (VBTLX).

FORBES: Choices in Portfolio Rebalancing

Perhaps you should go all the way to a cheap index fund, like Vanguard Index Total Stock Market, which has both low expenses (0.2% annually) and rock-bottom turnover (3% ).

FORBES: The hidden cost of trading

If you want to play it safe, one smart choice would be to buy the Vanguard Total World Stock Index Fund, which, as the name implies, tracks an index of the global stock market.

FORBES: Is the U.S. Debt Level Unsustainable?

The Vanguard Total Stock Market Admiral Shares (VTSAX) with an expense ratio of 0.06 percent was selected as his market index fund proxy.

FORBES: A Sharpe Assault On Mutual Fund Fees