Surprise, surprise, I'm the voice of dissent. I've already said most of this in another forum, so I don't wanna rehash it, too much. Anyway, I don't think it's a gimmick, at all -- not when it's done effectively.
It's come & gone a few times already, each time more polished than the last with the latest tools available at the time. Overall, it really hasn't changed that much.
Sorry, I gotta call you out on this one, Zensteve, but haven't you stated, in different forums, that you refuse to pay the money to go see one? So, how do you make this claim? 3D, today, is
completely different from it's earlier versions. It's like the difference between "Jurassic Park", and the claymation T-Rex in the original "King Kong".
To me, it feels totally natural, and it's just another tool to help suspend disbelief just a little bit more. When it's done right, there isn't a bunch of crap flying at your face -- it's more like they cut a rectangle hole in the wall, and what you're watching is actually taking place, on the other side of that wall. It's not a gimmick; it's not a fad. It's a new(ly effective) tool that a filmmaker can choose (or choose not to) use. I believe it's here for good.
That being said, I can echo the seemingly unanimous sentiment that it will not replace 2D (at least not any time soon). Not everybody likes 3D, some people get headaches from it, and not all films would benefit from it. Plus, those glasses are annoying; I only put up with them in the theater, cuz I like the immersive experience; not gonna wear glasses in my home.
Oh, and one last thing -- I think it's interesting that the only live action movie to ever effectively use 3D, in my opinion, has been "Avatar", and it's a bit of a stretch to call it "live action". Is this a technology best suited for animation?