Entirely depends on circumstance, if I am searching for porn and I go to Google I don't really want to be presented with hundreds of videos in the same category...I just want a porn video.
Also the usages are different, "video" is to manually film something yourself so would be good for a camcorder for youtube style site and "videos" would be a sales site or the former too...
Your dilemma is not that easy to sort out since it is not just a simple case of wondering whether or not you should use a plural.