Secular bull market may lasts for decades. If you buy gold in 2001 and hold till 2011, the appreciation is 700% in 10 years! This is not much compared to the gold bubble in 1980. If you buy and hold gold from 1976 to 1980, your gain would be 850% as the gold price rose from $100 to 850 per oz within 4 years time. However, we must acknowledge that any market operates with bulls and bears. From the above gold chart, after the crash in 1980, the gold market was in a secular bear for 20 years!
What drives gold price? Besides the demand and supply, gold is a barometer for inflation, global currency devaluation or simply put, the public confidence of the state of the economy. In general, when people have lose confidence with their currencies due to over printing of money or inflation, paper money depreciates and many would turn to assets such as stocks, properties and of course gold and silver!
How far the gold price goes depends on people's expectations, politics, economic condition, wars and many factors. There are 2 groups of people here: the goldbugs or the gold lovers who believe that gold represents protection from economic and financial chaos, and political and financial conservatism and they feel secure to own some gold.
The other group is the opposite, they do not think gold is a good investment as they believe gold does not pay dividends, nor does it represent ownership in a company. It's value is strictly tied to what investors are currently willing to pay for it. As long as there are more goldbugs willing to pay for the price, the gold price will continue to rally until the price is so high that buyers are not willing to pay for the extraordinary price. Technically, you'll see the volume declining as the price rises at the top of the bubble and the gold price is deemed for a crash.
When will it be? Maybe next year, maybe 5 years later, nobody knows. However, if you see your friends who have never invested in anything but decided to buy gold suddenly, that's the sign! But for now, I know the sentiment about the gold is still bullish.