You might also consider a small slice of commodities in your portfolio--roughly 5%-6% at the high end. But if you're retired, be sure to dollar-cost average into a commodity investment rather than adding it all in one go, because mistiming a commodities investment can erode any long-term inflation-protection benefit you hoped to gain.
Before you layer on additional inflation protection in the form of commodities, however, see if you already have any quasi-inflation hedges in your portfolio. For example, emerging markets tend to be heavy on basic-material producers, and they in turn are beneficiaries of higher demand and prices; check your portfolio's exposure to Latin America and developing Asian markets.
Also look at your portfolio's stake in energy stocks. They're not the same as owning commodities directly, but they have a fairly high correlation with energy prices, and energy is a major component of most commodities indexes.