Oh I agree, if it's done right the 3D effect is a fun little extra, nice to have. It's just that it's been pushed by Hollywood as the future of film so much that people are apathetical about it now, as you yourself found out with your missus.
I look at it like those Dolby psuedo-Surround effects... they're not going to change the world, but they can improve immersion a little bit.
What I'm looking forward to is
Super Hi-Vision. You know how an iPhone 4 has unbelievable sharpness on that tiny screen because of the high resolution and very fine dot pitch? Imagine that multiplied by four and on a 60" plasma screen. It will have better resolution than real life, just like they said in
Futurama.