The best model I have seen for gold prices suggests they are essentially a function of real interest rates. I have a blog post here that links to various discussions of the model, from way back in November 2010. 

Yesterday, May 16th, Bill Gross of PIMCO was on CNBC talking about the very same model for gold prices. The video is posted below.

I think Eddy Elfenbein of Crossing Wall Street deserves a lot of credit for this excellent model.

Manager of the worlds largest bond fund says Druck's retirement is the end of the "Old Normal".