If people start selling off their stashed coins the halved block reward will pretty much not affect the Bitcoin market because there will be still enough coins in circulation and there will be no shortage in supply thus the demand will be the same I guess. I don't think that the price will increase a lot after the halving though. We have to keep in mind that there is a whole lot more Bitcoins stored in wallets that could enter the market at any time and crash the price again.