Video quality and sound quality are both important. No bones about that.

But, suppose hypothetically you had to choose between two versions of the same programme, say a movie, where one had crystal video, but poor sound, and the other vice versa had poor video, but crystal sound, which would you choose to view?

I think I would choose crystal sound and poor video over crystal video and poor sound.

For a movie I would be inclined first to try the best image and see if the sound is acceptable because I usually put more conscious attention to the information of the events from the video than from the audio. But beyond certain level, the poor audio is less bearable for me than the poor video. Time ago I watched a couple of movies encoded with RealPlayer at very low resultion and it was possible to have a good time until the end if you accepted the very blurred images like you accept the raindrops in a window glass; but the thin distant dull audio of some cam captures "decouples" too much from the scenes, is harder to integrate for me and I quit soon.

It's interesting that the information through vision varies depending on the amount of light received (day, night, closed eyes) or the presence of foreground objects in the field of view, but our "audio channel" is always turned on at 100 % receiving waves of data of the surroundings, even from behind the walls. In some way it would seem a more reliable sense that vision; at least it is for the nightime survival of many animals.

At this moment I think that if there was a big degradation I'd choose the movie with the best audio; and the one with best video if the losses were less severe.

i choose the one with good sound but poor video..probably because i've been conditioned to get used to bad video (i.e old school tv's), but with bad sound, its something that you expect to work properly, and if its below an acceptable threshold, you just kinda cringe at it.