Interesting to read that precious metals are at 25-year highs:
http://www.financemarkets.co.uk/2006...hit-new-highs/
http://news.bbc.co.uk/1/hi/business/4864098.stm

I would have thought that with stocks rising that we'd be seeing less investment in "safe" investments such as gold.

I find it a little odd that we're seeing a combination of high investment in housing, stocks, and metals. Is this a symptom of heavy debt - ie, borrowing to invest?

What you're seeing is a huge trade in debt. Money is borrowed in low interest countries moved to high-interest countries for investment. The fact the major investment sectors are well invested in shows the extent and dangers of the debt bubble funding it all.