I'd sell when it hits about 900 or 1000 USD. I doubt it will go any higher than that especially since half of the possible amount of Bitcoins that can be mined have already been mined, mraning a crash is imminent.
How exaclty the fact that half of the bitcoin have been mined already correlates with a possible crash?
A lot of people will sell at 1000$ but don't be so sure that it won't go higher. After all we have seen a lot of flash crashes followed by flash rises.