While it's a problem when theaters don't schedule a 2D showing of a film at the same time as the 3D, I have to observe:
The opposite extreme of sneering "get with the times!" if someone doesn't prefer the 3D version of a film, is mindlessly repeating "3D is a stupid fad! It always has been, it always will be!"
Unfortunately, people who say that are equally wrong headed. The 3D "fad" we are seeing now is partly the result of new filming technologies. This isn't red/blue Crackerjack Toy 3D. The authentic 3D films coming out are filmed stereoscopically. The better films are beginning to explore how to use 3D to create new kinds of shots and new kinds of scenes. 3D isn't going anywhere.
The other reason for the 3D surge is it is a way to make the theater experience unique once again. Using the logic of some people in this thread, motion pictures should never have been shown in widescreen, with THX sound, because nobody had a widescreen television and a surround sound system at home, once upon a time. The fact that 3D showings make a unique event to draw people into going out to the movies is in fact, the point. The thing is, if it's a good experience, then it's not really a cheap gimmick.
Some people may not like the 3D effect personally, or may have physiological problems with it; that's perfectly reasonable. But by the same token, it's not going away this time, because the concept for truly three dimensional video/film displays is being enabled by a more mature technology.
Of course, it's easy to call it a gimmick because of the requirement of special glasses to view it. That is, indeed, a remaining hack required to make it work. In time though, that barrier will be removed as well. (And should solve comfort problems for people with a physical problem.)
In that sense, it is important that a lot of major films are being filmed with true 3D cameras today, because those films are futureproofed. The three dimensional information exists, thus it can be rendered into viewable form via more advanced techniques in the future. (Such as projection screens that don't require the viewers to wear glasses or sit in a specific spot to get the 3D effect.)