Not necessarily the most ideal, but I think the NCR ending is most likely to be canonised. NCR is the most established faction and I've got an inkling that Bethesda will want to stick to the status quo. Also, its considered the most 'good' (I feel sick saying this) ending, and you know what Bethesda's like...
Obviously, I want a House ending. I think it offers the most change while allowing the NCR to survive, which means the Core Region won't be messed with too severly, as it would be with a Legion ending. But I'm biased, of course