I disagree. 3D movies don't always suck. While I admire Walter Murch for his work in films (who the hell doesn't?), and I admire Ebert greatly as well, there's no reason 3D films can't have a place along with 2D films in theaters. I have personally never had a headache or problem watching a 3D film, and some films definitely benefit from it. I thought that "The Green Hornet" and "Tron Legacy" were both crap and without the 3D to keep me interested, I would have left the theater. (Ditto for "Avatar," by the way, which had a script just as stupid as the aforementioned two films.)
Good 3D films add a bit of fun to the precedings, and in the hands of a good film maker even more than that. Anyone who's seen Hitchcock's "Dial M for Murder" in 3D, and "Kiss Me Kate," will understand immediately what I mean.
What I dislike at the moment is the rush to turn any action/adventure film into 3D, particularly post conversions of films which were not filmed with 3D in mind. And of course the jacked-up ticket price doesn't help, either.
But I don't think that all 3D sucks. Overgeneralizations never make sense.