Asking about video players or audio players separately would already involve the risk of getting a lot of duplicate answers, but a question asking one about all "media" players had made it all useless in my opinion, especially by the fact that the thing is impossible to improve and keep up to date. Any new answer would make the post more boated.
There are no "media players" (that would cover all media files) other than (some) video players: all video players are audio players too, but, having that in mind, it is not a reason not to have a separate question about audio players only. Or about video players only. Any such question would be a duplicate of the one above until that is closed. But I am not sure how to articulate what the problem really is in the terms of rules of the community: but there is something wrong with that question.
From time to time I look at it trying to find (or add ) something new on the matter, I have also contributed a bit editing some answers, but from the very beginning my conviction is that a better thing would be just to close it and have two separate, systematic ones: one about video, one about audio.
Of course there are players that play both: video players do. But after a few more steps their ways have to part in order to have a good application going. The way the experience is developing on the long run is very different for music and for movies.
During all my experience with music and movies on a computer I felt that a good audio player and a good video player, or at least that are worth mentioning, are two different things. I never used something like windows media player and don't want something like that in Linux. I feel a such question doesn't look good, and it gets uglier with every new answer.
Trying new questions now would doom them to be closed as duplicate. Before trying I need a straightforward meta answer on this.
What to do? (Already flagged that trying to make a point.)
(I might very well be too subjective on this matter, but that is a good reason to want to find what Ubuntu main-trend is on this.)