A combination of physical assets, fiat money, gold and bitcoin, as diversifying is often paramount to stability.  But if I had to choose one of the other... I honestly don't know.

Countries like China and India are now accumulating large sums of gold, so they seem to think that's where the future lies.  But at the same time, there are pretty obvious manipulations going on in the gold market which would make me wary of investing large sums.

Bitcoin offers tremendous potential for the future, but without the aid of a crystal ball, it's impossible to know how it's going to play out.  So for that reason I'd say bitcoin is the riskier investment, but has the potential for a much larger return if it does pay off.