There's MPlayer...

http://www.mplayerhq.hu/design7/news.html

And in the OS X context the better form of it, MPlayerX: http://mplayerx.org/

Which has taken over Perian / VLC almost entirely, for me. Perian has been utterly fantastic, a near ideal passive improvement for everything, but MPlayer smokes everything in performance.

I find mplayerx extended better:

http://www.mplayerosx.ch/

I love movist. http://code.google.com/p/movist/

It might "seem" that way.

But as others have pointed out, there is indeed another major open source media player.

At what point did VLC start using the ffmpeg libraries?

If I'm not mistaken mplayer has used them since its inception.