Portfolio construction begins with the most basic allocation between investments that offer a greater chance of appreciation (stocks) and those that provide portfolio stability (bonds). There is no such thing as a safe investment that pays market rates of return.

Here are several articles on the wisdom of the risk-return decision:

Portfolio Allocation: Risk-Return Mix	Investing Mostly in Bonds Means a Lower Lifestyle in Retirement	CAPM: The First Factor of Investing	The Whip Cracks Both Ways
Appreciating Assets Part 1: Stocks and Bonds	Appreciating Assets Part 2: Other Investments	Gold Mining Companies Glitter More Than Bullion	Hedge Inflation Risk with Hard Assets
Investment Strategies Part 1: Rebalance into Stable Investments in an Appreciating Market