A suggestion on the Roth: instead of precious metals, how about a more diversified commodites allocation? Something like PCRDX.
PCRIX has a lower fee structure and can be bought through vanguard with a $5000 minimum. Considering its an institutional fund, thats pretty good.
Note that commodities funds like this are EXTREMELY volatile and you can lose a whole lot of money quickly. Note also that some analyses show it to be a very good counterbalance to stocks...even better than TIPS.
Commodities tend to offset inflation pretty well, and are particularly effective against unexpected inflation.
The big difference between commodities and metals alone is probably psychological. People "flock to the safety of gold and silver" during some bad times, they dont necessarily do that with commodities. More sophisticated (or bored) investors who look at the historic volatillity reduction commodities bring tend to move in and out of them in an unpredictable manner.
Still, it may not be a bad idea to hold 5-20% PCRIX, and I've seen plenty of data to support that (and a bunch that refutes it).
See Raddr's finance web site for more on this, he's a PCRIX afficionado. Maybe he'll see this and chime in a few pieces of data.