2D or 3D
When movies started coming out in 3D, for the first while I saw something in 3D if it was available — The Adventures of Tintin, Alice in Wonderland, A Christmas Carol, Coraline, Despicable Me, How to Train Your Dragon, Up. But the only movie where the 3D was significant was Avatar — the other movies would have been just as enjoyable in 2D. So now I see movies in 2D, since I don’t think it’s generally worth the extra money for the 3D version — The Avengers, Prometheus.
I’ve seen a small number of IMAX movies (I just looked at a list and there are a lot of them). One I remember that was in 3D was Space Station, a documentary about the International Space Station — that was a good one.
One movie that’s being rereleased in 3D I will go and see — Jurassic Park.