From the point of view of 'conveniently disributed stores of wealth' coins are hard to beat. I have been interested in bulliondirect but have not yet decided they meet my requirements.
Junk silver has been my choice, from coin shops and ebay (great while Microsoft/ebay/paypal were offering...
riskfree:
Please find volatility of the following daily closing prices:
T+1=79.40, T+2=82.71, T+3=79.40, T+4=82.71,T=5=79.40, T+6=82.71... T+37=79.40,T+38=82.71
Odd days close at 79.40 and evens at 82.71.
I pay near minimum for data to IB (tax advantaged account). The best info I have is for the current contracts, where I see 10 months on ES, 18 on GC, and 23 on ZC.