National Geographic Magazine's January 2009 issue has an article about gold:
While investors flock to new gold-backed funds, jewelry still accounts for two-thirds of the demand, generating a record $53.5 billion in worldwide sales in 2007. For all of its allure, gold's human and environmental toll has never been so steep. Part of the challenge, as well as the fascination, is that there is so little of it. In all of history, only 161,000 tons of gold have been mined, barely enough to fill two Olympic-size swimming pools. More than half of that has been extracted in the past 50 years. Now the world's richest deposits are fast being depleted, and new discoveries are rare.
I cannot understand why people and central banks are willing to pay so much for gold. It has less utility than platinum and silver. Most items that rely primarily on scarcity to attract consumers eventually lose demand and their high value. With gold, however, consumers can't seem to get enough. At least gold's value is not artificially inflated, as with diamonds (see DeBeers litigation). Yet, I cannot think of a single other product whose attraction has such little correlation with its utility.
With platinum and gold selling at similar prices, I would probably go for the platinum. For now, my only precious metal is silver, which I own through a silver trust ETF (SLV).
Update: The print edition of the National Geographic piece has two charts on page 42 and 43 that are worth a look. One is called, "What it's worth," and the other is called "How it's used." If readers find a link to the charts, please let me know or please post a comment.