Having been to a number of Broadway shows over the years, I can't recall anyone ever eating during a stage performance. Maybe a sip of water or a bite of a protein bar snuck from a handbag, but never openly eating. Unless, of course, it was something called a dinner theatre, in which case you are served a meal during various performances.
Now movie theatres are an entirely different animal. If you guys are disturbed by a little crunchy food, you wouldn't survive 5 minutes in the movies in an African-American neighborhood. People shouting warnings or opinions at the screen, or crying, loud arguments, or boisterous laughter; it's quite an experience.
But like going to a ballgame and having a hot dog and a beer, having a soda and popcorn at the movies goes hand in hand.
With the overdriven, ear drum splitting Dolby surround systems in almost every theatre (and don't forget IMax 3D), I don't know how you can hear anyone eating. Heck, in an action adventure flick, you couldn't hear a woman have a baby or someone get murdered, let alone a noisy bag of snacks.
Having said that, we almost always order a Coke (the small one that could satiate a village), a small popcorn, and a nachos and cheese. The nachos are just little round corn crisps that are served in a box with a small tub of melted nacho cheese sauce.
Now, the best way to enjoy this is to take a chip (crisp), dip it half way into the nacho cheese, then dip the cheesy crisp into the popcorn so some of the popped kernels stick, and voila'! A mouthful of cheesy, crispy, popcorny goodness.