I'd think 75, because as I have noted before, this is an election year, and if the Fed feels like they need to do a lot of easing, they will want to get it done before the election season is really under way, so as to maintain political neutrality.
50 may be the necessary compromise, because of the parlous state of the dollar.
All kinds of symbolically important stocks are getting the living crap beaten out of them: INTC, GM, C, to name three. The collapse of the techs is especially disconcerting, as they qualify as cyclical plays, and they're trading like a deep recession is baked in the cake.
Given that, the Fed will want to go lower than neutral, and that means 50, which will put them at 3.75, 25 below the low end of neutral. 75 if they want to get it done before the election season gets truly serious.