The one-inch PUSH, imo.
I spent an earlier part of my life looking at various things like the one inch punch, (and chi, dim mak, ninjas and everything else). I'm of the opinion now that it doesn't work very well. Even if it did, it's not very useful. It would be MORE useful to be able to hit hard while executing good footwork as opposed to standing still and gathering your "chi" in preparation to hit.
But that's just me.