Quote from trefoil:
Long term, as interest rates rise so too will the dollar. It's sensitive to interest rates, which are sensitive to growth, and while that will be slow, it will be steady.
The rivals: the euro is hobbled by its completely dysfunctional structure, the yen by Japan's completely dysfunctional political system, which now that I think of it is actually the euro's problem too.
Gold is sensitive to interest rates: as US interest rates rise, its cost of carry increases. I'm sure someone around here has mentioned this somewhere, but if so, I missed it.
China, of course, will allow the yuan to gradually weaken against the dollar, or at least hold steady or rise only very very insignificantly, while all this happens. This will continue until some US pol notices, at which time it will rise, and once the furor dies down, it'll be back to steady as she goes.
This will continue until it can't go on any longer, but that's many years down the line.