RE: free real-time stock quotesgold has been a good investment but the commodities boom is fairly widespread and includes many different types of metals, minerals, food and related fertilizer stocks.
If you are primarily looking at precious metals, you should consider silver. Silver has outperformed gold this year and has historically been more volatile. The ratio between gold and silver has been stretched to near 60 when the historic ratio is closer to 16. There are fewer profitable silver miners but there are several good picks including SLW, CDE, FR.to, FVI.v.
The base metal inventories have been climbing due to slack demand from the world's economies in recession. However growth in the emerging markets will eventually bring down inventories and so many have invested in base metal miners in copper, zinc, lead,etc. This has caused base metals prices to climb even as the inventories climb.
The emerging markets will also demand a much increased supply of food over time as their GDP grows. That means more fertilizer and it's components. I am holding aaa.v, mak.ax and lgdi.ob.
Of course AAB.to covers many of these bases with their junior and early stage exploration plays in metals and potash.
Good luck. I think you should diversify and hold more than just gold.