robo - I completely agree w/ your ordering. TSP matching is a no-brainer. Roth IRA's are also excellent. It's just too bad they have an income limit and we're not allowed to put more in.
gwert - you're asking the exact same question I have. Where to put our TSP money w/ a declining dollar -- and even a potential collapse. This isn't doom-and-gloomer talk; it's just a possibility, but a signficant one, that should be faced.
I don't know!

The ideal would be a commodities fund. There are plenty of ETF's for this (i.e. dbc or ige), but we don't have any such choice.
It could be that stocks will go up (or hold their own) w/ a dropping dollar if foreigners snap them up on the cheap. But, a declining dollar and a hurting consumer faced w/ rising prices will also weaken the world economy.
International stocks would seem good, but China's market is _certainly_ going to burst. It's an obvious bubble and even participants are just going along for the ride and hoping to get out in time. Many are waiting till the Olympics, but who knows if a panic won't hit before then as smart money heads to the exits.
Bonds -- it would seem so since the Fed is cutting rates, but the longer-term rates have been going _up_ in contradiction. Rates may continue to rise to keep foreigners buying our debt while the dollar keeps dropping.
Then there's the G fund. Safe? It doesn't really even keep up w/ _true_ inflation (the housing bubble was never factored-in). And based on short-rates, and w/ a dropping dollar, it's losing it's real value.
It seems TSP participants have little choice. The gov't should just match our money and let us direct it into the brokerage we choose.