If I remember correctly, the nice thing about a 4k display is that you use the cheap passive 3d glasses and still have 1080p to each eye. I don't really care much about 3d though.

4k may be a discernible upgrade in the projector realm, but probably not in TV's. So just 4k alone is not enough to push it as the next big thing. 3D TV sales have been pretty poor overall. I don't know if having passive glasses with 1080p to each eye is a big enough selling point to turn things around.