Money: that store of value needs to be stable in terms of real world items. That is what the central banks take care off (indeed at will, look at QE, look at the promised bond bailout in Europe to ease the minds in the financial world). Inflation and deflation should not be high.
Limited or not is not the issue. It is a bigger problem that you don't know what you can buy today or tomorrow with a fixed amount of bit coins.
But because it is limited, you can buy more and more ->deflation.
And the various crack downs lately -> inflation.
So bitcoin, as has been mentioned before, is not suitable as money, but is more like a commodity