Did a google of 2D vs 3D online polls...
http://aurorawienhold.deviantart.com/journal/poll/1144054/
http://whatculture.com/film/poll-do-you-prefer-2d-or-3d-films.php
http://www.fandango.com/movieblog/poll:doyouprefertowatchmoviesin3dor2d-589668.html
http://www.sodahead.com/fun/do-you-prefer-2d-or-3d-movies/question-2836195/?link=ibaf&q=&esrc=s
http://forums.redflagdeals.com/2d-vs-3d-movies-1346605/
http://www.thestudentroom.co.uk/showthread.php?t=1993719
Results are about 50% upwards in favour of 2D with two as high as 82-87%. So if Multiplex's aren't trying to scam us all then out-of-ten there should about 7 2D screenings and 3 3D screenings. This is not the case.
As Silverwook said new flick The Wolverine seems to be showing 50/50 which is cool. Perhaps that film's distributers have stipulated this, in which case good on them. But even then, it should be 70/30.
I wanna see SWEpVII on a huge iMAX screen in 2D (and not digital iMAX btw). I'd pay triple to see that lol