You may be surprised to hear (read) this, but prices vary by market.
I live in a small city in Saskatchewan, Canada. Prices here are $9.50 and a dollar more if it is 3D.
I have family in Calgary, Alberta, Canada (1 million+ population). Last time we saw a movie there the ticket price was $17. Add a popcorn or drink, that's another $5-$7 each. This was a couple years ago so things may have changed.
If you have kids, you either have to bring them or pay a babysitter to watch them. There's another $20-30 for a babysitter.
I used to rent movies all the time. Minimum one visit to Blockbuster a week. $5-6 a week is much more economical. However Blockbuster Canada went out of business so they could pay off their U.S. debt. At the same time, Rogers Video closed down a chunk of their stores, the one in my town being one of them.
Now its Torrents for me because I am out of options. $40 for the theatre is too much (including babysitter). That's also the cost of buying a Bluray thesebdays.... I'm not about to commit my money to that if I don't like the movie and never actually watch it.
So I torrent it, and if I really like it, I will buy it. Just watched The Expendables 2 last night... I enjoyed it, no real storyline but I was entertained (OMG, explosions!). Not really a movie I would buy but my wife _really_ likes it so we will probably get it.
Not many movies out there I want to watch more than once. All of the kids movies we download we end up buying.... Disney Cars (1&2) my son likes to watch each twice a week.