We watched one of the "now in theaters" movies they have thru Comcast's On Demand service. They usually cost a bit more ($9.99) than renting those that are out on DVD ($5.99). But they're all independent type movies that aren't in wide release, and not big release movies.
How much would we be willing to pay to watch a current big movie? Iron Man 3 has been out in theaters a few weeks now. How much might we pay to watch that tonight at home? I'd easily pay $25 to watch it at home tonight. Less than what it would cost for us to go out, maybe pay for parking, and pay the excessive price for movie snacks compared to what we have at home.
I think $25 is the sweet spot. $35+ we'd maybe do it if friends were coming over, but almost never for the 2 of us to watch at home.