With the exception of a few preview screenings I attended last year as part of a programming job, I've never gone to a movie in the theater without reading a few reviews and/or seeing a trailer first. It's just too expensive to get into the habit.
I have watched a number of things through Netflix and On Demand based on nothing more than the one or two-line description and the cast and crew listed. As you might expect, this has been a mixed bag, but not entirely without unexpected surprises (Hopscotch
, which I caught recently, was rather good).