Im so excited about the halving, whether you think its going to go up or down no one can argue that the uncertainty is gonna bring some volatility so us traders can finally make some good money again.
Well, after the last one on 2012-11-28 the price basically remained flat for 5 weeks.
There was a rally after that, true; but before and after that halving there were several other rallies and crashes, which can hardly be consequences of it. So, there is no good reason to think that the Jan--Apr 2013 rally was connected to it, either.
Things may be different this time, of course. However, I would guess that the only direct effect will be a drop in the hashrate. If that happens, there may be indirect negative effect on price.