With movies I don't bother with them unless they have descriptive audio, at which point you've got music, sound effects, and two somewhat parallel speech streams going on. That's high informational content.
I did an entire CS degree at 800 words a minute. I program in any programming language you care to name (including the initial learning) at that speed as well. For more complicated concepts I stay at that speed, but pause after every paragraph or so to chunk the content as needed. I'm doing this thread at that speed. Pretty much the only time I slow it down is pleasure reading or sometimes articles when i want to go off and do chores while I listen, but even then it's still faster than human speech.
In general i think answering these sorts of questions needs research that we don't have to my knowledge. Nothing in my personal experience or background really allows me to give you good definitive answers. The sample size to work with is pretty small and in all honesty there's not a lot of good research around blindness day-to-day in the first place.